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Time, Speed, Distance and Work- Solved Problems
by Total Gadha - Saturday, 6 October 2007, 07:28 AM
  cat 2010 cat 2011 time speed and distance xat 2008 mba 008I have been suffering from the writer's block lately and therefore I decided to do what I like to do the most- solving problems. To help all the CAT 2010 aspirants on Total Gadha, I decided to hunt TG quant forum for the time, speed and distance problems and solve them. What a treasure I discovered! Some of these problems will baffle brains of even some of the most experienced instructors. I am posting all the problems I solved along with their solutions. All of you please first try to solve the problems on your own and then see the solutions. This way, you would appreciate the solution to many of these problems. Also, notice that I again used only ratios to solve these problems. Still no equations.


cat time speed and distance


cat time speed and distance
cat time speed and distance
cat time speed and distance
cat

I shall have to end here and leave the rest of it for my CBT Club students. I shall cover some problems based on this in the CBT Club this week.

 

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Re: Time, Speed, Distance and Work- Solved Problems
by unbreakable belief !!!!! - Saturday, 6 October 2007, 09:43 AM
  hey sir
you are  genius approve
keep continuing this.it is very useful for us.
Re: Time, Speed, Distance and Work- Solved Problems
by Sanju P - Saturday, 6 October 2007, 10:15 AM
 

Hi TG,

Thanks a Zillion! smile

SP smile

 

Re: Time, Speed, Distance and Work- Solved Problems
by sonu kumar - Saturday, 6 October 2007, 02:01 PM
 

thanks

It's a great gamut of TSD ....

thanks again for jiffy

take care

Re: Time, Speed, Distance and Work- Solved Problems
by Purav Parekh - Saturday, 6 October 2007, 02:44 PM
 

hey TG!

shoudnt the answer in second last problem be 16?

As, n(n+1)w/2=129w,

for n=16, n(n+1)/2=16x17/2

                          =8x17

                          =136 >129

Re: Time, Speed, Distance and Work- Solved Problems
by fundoo bond - Saturday, 6 October 2007, 03:51 PM
  hi TG,
i saw it coming...smile
the one compiled source ll definitely help a lot...
thanks ll be a too common wod to say... big grin
Re: Time, Speed, Distance and Work- Solved Problems
by Total Gadha - Saturday, 6 October 2007, 08:05 PM
  Hi Purav,

Corrected!

Total Gadha
Re: Time, Speed, Distance and Work- Solved Problems
by Gul Gul - Monday, 8 October 2007, 10:46 AM
 

Hi TG

Hope u r doing gr8 as usual...nice topic...

1 doubt in 1st question is it not possible that point T is between M and S....???

Re: Time, Speed, Distance and Work- Solved Problems
by Total Gadha - Monday, 8 October 2007, 03:46 PM
  Hi Gullz,

If A is traveling for a longer time with his normal speed, he will travel a longer distance, no?

Total Gadha
Re: Time, Speed, Distance and Work- Solved Problems
by Kunal Gupta - Monday, 8 October 2007, 03:54 PM
  In wall wala Question,what would be the mathamatical formula formed?
Re: Time, Speed, Distance and Work- Solved Problems
by Gul Gul - Monday, 8 October 2007, 05:31 PM
  So silly of me thanks Sir.....
Re: Time, Speed, Distance and Work- Solved Problems
by roomki agarwal - Tuesday, 16 October 2007, 01:26 PM
  HI TG SIR, D ANSWER 2 D 4TH QUESTION "D DISTANCE BETWEEN MR SHARMA'S HOUSE 2 OFFICE Z INCOMPLTE.SIR PLZ REPLY IT.
Re: Time, Speed, Distance and Work- Solved Problems
by Contender ! - Tuesday, 16 October 2007, 04:06 PM
 

Hi TGites,

      This is my first post here but then it just marks the begining of a long innings which i intend to play, even if I get into a B-School of choice.

The reason i am posting here is bcoz i thought there was a flaw in first questions solution, i might be wrong. TG when you say that 'A' would have covered 3x/2 distance doesnt that mean that this is something we cannot take into consideration when finding the ratio of speeds of A and B here, which is based on the assumption that A actually covers X distance and not 3x/2 ? And hence I would request you to explain 4th line of 1st questions solution ..

 

Thanks for all your efforts

 

Regards,

Contender

Re: Time, Speed, Distance and Work- Solved Problems
by Total Gadha - Tuesday, 16 October 2007, 04:58 PM
  Hi Contender,

If I need to find the ratio of speeds, I need to calculate the ratio of distances traveled in the same time. If A were traveling at his usual speed he would have traveled 3x/2 in place of x. I'm not saying that he traveled 3x/2 but since i'm taking ratio of A and B's normal speed, I need to find total distances they travel in the same time with their normal speeds. As A is traveling a part at 2/3rd of his speed, we need to convert this distance into what he would have traveled at his normal speed in the same time.

Total Gadha
Re: Time, Speed, Distance and Work- Solved Problems
by ankit tulsyan - Thursday, 18 October 2007, 11:55 PM
 

nice piece TG.

permit me to point out a few things.

The question with two trains crossing with speed 80kmph and 65 kmph,you didn't mention the direction of crossing,so relative speed could be either 15 or 145

In the very next question,you state "every clock will show the correct time when it is late or fast by hours that are multiples of 12." This holds only when am/pm distinction is not mentioned.If it is (like in the question ),then they will show correct time if they are late or fast by multiples of 24 hours.right?? 

 

Re: Time, Speed, Distance and Work- Solved Problems
by Total Gadha - Friday, 19 October 2007, 07:48 AM
  Hi Ankit,

Both points taken. smile

Total Gadha
Re: Time, Speed, Distance and Work- Solved Problems
by Marvish Aghera - Tuesday, 30 October 2007, 06:27 PM
 

This sum all are good.

but first u want to put basic fundas of time speed and distance.

means u want to put first of all basic formula of time speed and distance bcoz very medium capacity student will not be able to understand this sums.

so plz first put that formula and than after u put this all sums.

Re: Time, Speed, Distance and Work- Solved Problems
by Umesh Kathuria - Tuesday, 30 October 2007, 10:54 PM
  Hi Marvish,

You can refer to the following Threads by TG:

http://totalgadha.com/mod/forum/discuss.php?d=269
http://totalgadha.com/mod/forum/discuss.php?d=448
http://totalgadha.com/mod/forum/discuss.php?d=10

and there is only one formula for Time Speed Distance  ;).


Regards
Umesh Kathuria
Re: Time, Speed, Distance and Work- Solved Problems
by smita chatterjee - Wednesday, 23 January 2008, 05:05 PM
 

hi TG sir,  thanks for the awesome work u r doing here...i find ur articles and materials realy helpful. i am stuck at a particular sum and would be really grateful if u could solve it for me.the sum is:

I save 2 hours while travelling 96km at a speed at which i cover 1 km more than the distance i had intended to travel in 1 hour 15 mins. What is my current speed?

Re: Time, Speed, Distance and Work- Solved Problems
by Madava Hegde - Thursday, 31 January 2008, 09:55 AM
 

Hi SMitha,

I have solution for this.But i really dont know the shortest As well as smartest way to do this problem....wide eyes...

Total distance covered is 96..

96 = s*t here s=Intial speed which is not equal to actual spedd.

t= time taken.

 

Now in qstn it is mentioned that he will take 2 hours less if he travel with spedd s1

so, t1=t-2

s1=(s*5/4)+1 And s1*t1=96

subtitute values of s1 & t1

((s*5/4)+1)*(t-2)=96

d*5/4+t-5*s/2-2=96

we know d=96...

so 120-2+t-5*s/2=96

t-5*s/2=-22

we know t=96/s

22=5s/2-96/s

solve this u will get quadratic equation like.

5s2-44s-192=0

Values of s will be s=12 or s=-16/5...

second value is not possible since it is negative(Dont worry abt indepth meaning of negative sign...It has lots of hidden things)

if s=12...s1=12*5/4+1

so s1=16km/h....

AM i right?..IS the soln is 16 knm/h?...

If i am wrong please correct me...Let me know if some short cut methods are available for this...

Re: Time, Speed, Distance and Work- Solved Problems
by Juggler . - Friday, 20 June 2008, 01:59 PM
 

Hi Sir,

Need to apply your logic to solve this one:

Two cars leave simultaneously from points A and B on the same road in opposite directions. Their speeds are constant, and in the ratio 5 to 4, the car leaving at A being faster. The cars travel to and fro between A and B. They meet for the second time at the 145th milestone and for the third time at the 201st. What milestones are A and B?
 a. none of these  
  b. 78 and 234  
  c. 103 and 229  
  d. 102 and 245  

 

Thanks

Re: Time, Speed, Distance and Work- Solved Problems
by dibyaranjan mallick - Friday, 4 July 2008, 10:27 PM
  There is no Time-n-work question here. Sir, pls post some article on TW.
Re: Time, Speed, Distance and Work- Solved Problems
by avinash mohanty - Thursday, 10 July 2008, 06:49 PM
  in the first question..when we say..tht if "A would hav travelled at his usual speed then he would hav travelled 1.5*x +d wouldnt it mean tht B should travel a lesser distance??? i.e..2*d-(x/2)??
Re: Time, Speed, Distance and Work- Solved Problems
by Forrest Gump - Saturday, 12 July 2008, 04:41 PM
 

Hey Juggler!

Here is how you can do it::

SInce the ratio of speeds is 5:4, thus distance will always be divided in the same ratio i.e 5:4. Suppose total distance is 9d.

For the first meet they 2gthr cover :: 9d

for the 2nd meet they 2gthercover :: 27d.

Till 2nd meet A covers :: 5/9 * 27d = 15d. Thus distance from A is 3d and from B is 6d.(145th slot distance)

In the 3rd meet together they cover :: 45d (adding 18d to 27d).

hence distance by A :: 25d. which is 7d from A and 2d from B.

Now if u scale this on a line, you see distance between 145 and 201 is 4d. thus 56 slots equal 4d. Means 14 slots equal d.

ALso 201 slot is 2d away from B and 7d away from A.

Hence 103 and 229 slots are the position of A and B respectively.

Regards!

  

 

Re: Time, Speed, Distance and Work- Solved Problems
by Shreyas Sinha - Wednesday, 5 November 2008, 05:10 PM
 

Hi TG

In the fourth question,let the usual time be u

t= 0                d                      t=u           [s=d/u]

t=0+30             d                     t=u+15       [1.25s=d/u+15-30]

t=0+15             d                     t=u-20       [1.5s=d/u-20-15]

Thus we get three eqns in 3 variables,which I am presuming can be solvedsmile.

Hence distance can be obtained. What say?

OK i found out why it cant be solved

Sorry for bothering

Re: Time, Speed, Distance and Work- Solved Problems
by ankita sharma - Wednesday, 5 November 2008, 09:19 PM
 

Hi TG,
I am new to visit this site .. so please can you help me out with some tips mail me at ankita_sharma774@yahoo.com  my problem area is in DI ... so please help me out ..

can i suggest you something please add DI and DS lessons also ..as you have quants and verbal  lessons 

Hey!,  What kind of person are you?

I'm surprised about - How can you manage to hit the nail on the head of the exact cause of problem?

I tell you one truth, after going thru this site i felt that you have made this site only and only to help me out
TG, I m really thankfull to you for NOT teaching me syllabus But teaching me "How to Think of CAT way".

This is the one of the best site, I ever seen on the net.

Thank You!

Regards,

ankita sharma

 

Re: Time, Speed, Distance and Work- Solved Problems
by gmatblr gmatblr - Friday, 21 November 2008, 06:44 PM
 

In the first Problem .....,

I am not clear with the distance covered by B.Below is my query:

I agree that if A were to travel at his usual speed after point R,he would have covered (3/2) x .  Hence the total distance is d + (3/2)x ,if he would have travelled with his normal speed.

However , in the above hypothetical case of A travelling with his usual speed after point R ,B should have covered less than 2d ? .The distance covered  by B is 2d when A travels at 2/3 rd of his speed after point R.But when A travels at normal speed ...more distanced is covered by A, Hence the meeting point for B should be less than 2d ?Why is it considered as 2d in both cases ?

I have scratched my head for over an hour and looked at the site for answers but still cud not understand ... how can we consider the distance travelled by B as 2d .

Distance travelled by B wd have been 2d only if A travels with his reduced speed after point R.

Would be greatful if someone,or TG Sir, can clarify my problem

 

Thanks

 

 

Re: Time, Speed, Distance and Work- Solved Problems
by gmatblr gmatblr - Sunday, 23 November 2008, 01:39 PM
 

 

 

CAN SOMEONE PLS RESPOND :

____________________________

In the first Problem .....,

I am not clear with the distance covered by B.Below is my query:

I agree that if A were to travel at his usual speed after point R,he would have covered (3/2) x .  Hence the total distance is d + (3/2)x ,if he would have travelled with his normal speed.

However , in the above hypothetical case of A travelling with his usual speed after point R ,B should have covered less than 2d ? .The distance covered  by B is 2d when A travels at 2/3 rd of his speed after point R.But when A travels at normal speed ...more distanced is covered by A, Hence the meeting point for B should be less than 2d ?Why is it considered as 2d in both cases ?

I have scratched my head for over an hour and looked at the site for answers but still cud not understand ... how can we consider the distance travelled by B as 2d .

Distance travelled by B wd have been 2d only if A travels with his reduced speed after point R.

To put it other way .

Say total dist is 100 .

A With reduced speed  travels 55km and B travels 45 km

Had A travelled with his original speed he would have covered 60 km and in which case B wd have covered 40 km . Similarly , B in the above example must be less than 2d.

Would be greatful if someone,or TG Sir, can clarify my problem

 

Thanks

Re: Time, Speed, Distance and Work- Solved Problems
by Total Gadha - Sunday, 23 November 2008, 11:41 PM
  hi gmatblr,

please read the solution again. in oncase distance traveled by B is 2d whereas in the second case it is 2d - d/4

Total Gadha
Re: Time, Speed, Distance and Work- Solved Problems
by saurabh yadav - Wednesday, 1 July 2009, 05:15 PM
  tg ,
     why have u solves the question using hpothetical assumptions [3x/2..,etc .]
plz xplain.
        thanking u in anticipation.
 
Re: Time, Speed, Distance and Work- Solved Problems
by Varun Agrawal - Monday, 13 July 2009, 05:54 PM
  Hi,

 Dont you think that in the problem where a train runs at a speed of  75kmph without stoppage and 60kmph with stoppage between the same distance, there is some problem. I m not able to get any logical point to it. How to approach the question and how did you proceed.. ???
 Can you please help ??

Thanks
Varun
Re: Time, Speed, Distance and Work- Solved Problems
by - SK - Saturday, 25 July 2009, 01:23 PM
  TG Sir,
Thank u sooooo mch for such a wonderful article...

Shiva
Re: Time, Speed, Distance and Work- Solved Problems
by - SK - Saturday, 25 July 2009, 06:38 PM
 

Hi TG sir,
Not able to understand the escalator problm...sad
Can sm1 help me.. ..


Actually my doubt is when the time taken by them is same.. how can we equate the upstream and down strem speeds.. Distances here(steps covered) will not be taken into account kyaa..confused a little..

plsss sm1 hlp me out as soon as possible..

-shiva 

Re: Time, Speed, Distance and Work- Solved Problems
by ravindra kumar - Thursday, 6 August 2009, 01:17 AM
  hi sir..
in the 1st question..u had written that the ratio of their speed will be
(d+3x/2)/2d.......bcoz a would have traveled 3x/2 distance in the same time if its speed would have been the same......but in that case the distance traveled by B would have been lesser than 2d.
correct me if i m wrong.......
Re: Time, Speed, Distance and Work- Solved Problems
by dilip rathore - Thursday, 6 August 2009, 05:07 PM
 

these are the best questions ,, almost of the kind that we see in CAT papers. thanks a lot man.. smile))

this site has made my office hours BLISS :P

Re: Time, Speed, Distance and Work- Solved Problems
by amit singh - Tuesday, 15 September 2009, 03:52 PM
  it doesnot have to meet at the point s.b wil still cover the same distance 2d in that time n with its normal spd wil cover d+3x/2.
Re: Time, Speed, Distance and Work- Solved Problems
by abhinav prakash - Thursday, 15 October 2009, 10:26 PM
 

hey TG,

in the two clocks prblm, arent the clocks supposed to show correct time (i.e.,7 p.m. again) after 24 hours?? Correct me if I am wrong.

So, the answer should be 60 days. Shouldnt it??

Re: Time, Speed, Distance and Work- Solved Problems
by Nikhil Jain - Tuesday, 20 October 2009, 10:50 PM
  Hi TG.
Thanks a lot for this article. This helped me to solve many other questions.
i have few doubts in this:

Is their any other way by which the fifth question from the bottom and the 1degree(integral value)can be solved? Because i did not understand the explanation.

Regards,
Nikhil
Re: Time, Speed, Distance and Work- Solved Problems
by Double O Seven - Thursday, 22 October 2009, 02:22 AM
 

Hi Abhinav,

Since clocks have a 12hr dial face normally, it would show the same time after a loss/gain of 12hrs. If it were a 24hr clock (as seen in railway stations) you would be right.

Re: Time, Speed, Distance and Work- Solved Problems
by Double O Seven - Thursday, 22 October 2009, 02:40 AM
 

Hey Nikhil,

The minute hand chases the hour hand at a speed of 11/2 degrees/min. You can find the related explanation here. At Noon both the hands are together. At One o'clock the angle diff is 30 deg. Now for a angle diff of one degree the mintue hand has to traverse either 29 or 31 degrees at a relative speed of 11/2 deg/min. The time taken would be 29*2/11 and 31*2/11 respectively. Both are non-integers so ruled out. We now check all such cases i.e 59*2/11 and 61*2/11 for 2 o'clock, 89*2/11 and 91*2/11 for 3 o'clock and so on ..

Two such cases yield integral values -- 121*2/11 [(30*4+1)*2/11] and 209*2/11 [(30*7-1)*2/11].

Hence answer is 2.

Re: Time, Speed, Distance and Work- Solved Problems
by sriram Kothandaraman - Friday, 23 October 2009, 05:54 PM
  Dear TG Sir, I recently came to know about your site. I am really thankfull to you for posting a wide range of topics. Regards,
Time, Speed, Distance and Work Solve this Simple Problem ?????????
by Pallav Jain - Wednesday, 18 November 2009, 12:01 AM
  Hi Guys ! here is another simple but tricky question ???

A starts from home for his office. He travels downhill, then on flat ground and then uphill to reach his office. It takes him 3 hrs to reach the office. On the way back home A takes 3 hrs 10 min to reach home along the same route. The speeds downhill is 60 km/hr, on flat ground is 48 km/hr and uphill is 40 km/hr.

What is the distance between A’s home and his office?
144 km
148 km
154 km
160 km
Data Insufficient

Cheers !!!!!!

Pallav
Re: Time, Speed, Distance and Work- Solved Problems
by Pravin Vaidya - Thursday, 19 November 2009, 07:48 PM
  Hi TG
In 'dog and owner 'problem , the first statement of the solution mentioned about k as ratio of the speed of the
owner to that of his dog.
I think it should be the ratio of speed of the dog to that of speed of the owner.
Re: Time, Speed, Distance and Work Solve this Simple Problem ?????????
by Pravin Vaidya - Thursday, 19 November 2009, 08:13 PM
 

Hi Pallavi
the answer is 148 km....cheers...smile

 

Re: Time, Speed, Distance and Work- Solved Problems
by kanika arora - Saturday, 21 November 2009, 03:14 PM
  hi Frens !

A swimmer jumps from a bridge over a canal and swims 1 km upstream. After that first kilometer, he passes a floating cork. He continues swimming for another half an hour and then turns around and swims back to the bridge. The swimmer and the cork arrive at the bridge at the same time. The swimmer has been swimming with constant speed. How fast does the water in the canal flow?

  a0.5 km/hr
  b2 km/hr
  c3.5 km/hr
  d4 km/hr
  e1 km/hr


Regards

Kanika
IIMA 2010-12
Re: Time, Speed, Distance and Work- Solved Problems
by Pravin Vaidya - Saturday, 21 November 2009, 08:00 PM
 

Hi Kanika,

answer is 1 km/hr.

solution:

let u and v be the speed of the water and speed of the swimmer respectively.


so after passing the floating cork time required for the swimmer to reach the bridge is
(1/2) + (d2/(u+v)) + (1/(u+V))

[where, d2 --distance travelled by  the swimmer in half an hour.]

also the time required for the cork to  reach the bridge can be written as:
(1/U)

since cork and swimmer arrive at the bridge at  the same time we can equate both the equation.
i.e.
(1/2) + (d2/(u+v)) + (1/(u+V)) = (1/U) ----- (1)

also d2 ( distance travelled in half an hour) can be written as :

d2 = (v-u) *(1/2) --- (2)

replacing d2 in equation 1, we get

(1/2) + ((v-u)/2(u+v)) + (1/(u+V)) = (1/U)

solving the equation we get

u=1
so , the answer is 1 km/hr.....

cheers and beers ..smile

Re: Time, Speed, Distance and Work- Solved Problems
by kanika arora - Saturday, 21 November 2009, 08:29 PM
  hey thanx pravin but i cudnt get this step....

(1/2) + (d2/(u+v)) + (1/(u+V))
 why you have added 1/2 : what is this 1/2

kanika
Re: Time, Speed, Distance and Work- Solved Problems
by akash gupta - Saturday, 21 November 2009, 08:48 PM
  1/2 is the half hour which the swimmer swam after crossing the cork and reached the point from whr he traveled back
Re: Time, Speed, Distance and Work- Solved Problems
by megha zutshi - Wednesday, 2 December 2009, 04:08 PM
 

Hi TG,

In the first question, i am unable to figure out ur calculating for the first case where distance travelled by A is d+3x/2 and by B is 2d. If A travels more than the distance x, then the distance travelled by B should be       2d-(x/2). Similarly for the second case: distance travelled by A should be     (11d + 10x)/8 and distance travelled by B should be (7d/4)-((d+2x)/8)=    (13d-2x)/8. This on solving further does not yield the correct result. Please help.

 

Thanks!!

By the way great work!!

Re: Time, Speed, Distance and Work- Solved Problems
by Sagar Thakur - Monday, 7 December 2009, 06:13 PM
 

Any one can help me to solve this problem.....

 

If 20 men or 25 women or 30 boys can do a piece of work in 16 days by working 10 hours a day, then how many men with 10 women and 18 boys can do 3 ¼ times the same work in 26 days by working 8 hours daily?

Re: Time, Speed, Distance and Work- Solved Problems
by Aseem Mahajan - Thursday, 21 January 2010, 09:43 PM
  its a work problem from quantum cat by sarvesh kumar verma-
In a nut-bolt factory 180 workers are working for 6 hrs a day. Out of 180 workers there are some men,some women and rest are boys. All the workers can produce either nut or bolt or both of them. A man can produce 60 nuts and 80 bolts in each hour and a woman can produce 30 nuts and 60 bolts per hr. A man is thrice as efficient as a boy and 3/2 times as a woman. given that all men,all women and all boys produce equal number of articles of one kind (i.e., either nut or bolt) per hour.
1. working 6 hrs a day, how many nuts they can produce with 52500 bolt in each day? a) 17500 b) 26250 c)50850 d)can't be determined
2. in how many hours can 15 men,12 women and 8 boys can produce 12000 nuts and 8200 bolts? a)3 b)5 c) 6 d) none of these
3) if 30 women and 50 boys can produce 5400 bolts in one hour then to produce equal number of nuts in one hour how many men are required? a)30 b)40 c)50 d) none of these
4) if the manager of the factory wanted equal number of men, women and boys in his factory but the efficiency of a man,woman and a boy remains constant, then the change in production is- a)increased by 10% b)decreased by 10% c) increased by 8.33% d)none of these
Re: Time, Speed, Distance and Work- Solved Problems
by Amarpreet Singh - Sunday, 7 February 2010, 06:37 PM
  HI TG,

I need your guidance regarding my situation..

I read somewhere on net that IIM-A gives a lot of consideration to 10th & 12th marks... is it true??

I got 80% in 10th, but 60% in 12th. Ive done B.Tech in computer science with distinction (73%).. If I crack CAT with a very high percentile (say 99.8) and clear all sectional cut-offs with a year's work ex, then do i have a chance to recieve a call from IIM-A???

Also I am dead serious about CAT 2010.. Im working as a software developer and reach home 10 at night and leave at 7 (due to my long travel time).. How do i utilize the limited time ive got in most appropriate way???

Also I drive for around 2 and half hours (up & down included), how can I utilise this time? I mean do u have any audio files which can be useful???

Please reply back, it would be reallyyyyyyyy appreciated..

Thanks & Regards,
Amar
Re: Time, Speed, Distance and Work- Solved Problems
by ankit singh - Monday, 25 October 2010, 11:08 PM
  answer to the question MR.SHARMA is 15 k.m.
After estimating that mr.sharma will take 75 min. to reach his office at his normal speed , lets assume his normal speed is x kmph ,
we know 75 min. = 60 min. + 15 min. = 1 hour + 1/4 hour = 5/4 hours ,
now his speed after 50% increament would be x + x/2 = 3x/2 kmph,
now Speed * Time = Distance ,

       3x/2* 5/4 = distance ,i.e. 15x/8 = distance ,
going by the options ,which are 10, 15 , 5 , 20 and 25 only 15 is possible since any other options are not multiple of 15. only 15 is possible when x = 8 .

Time, Speed, Distance and Work- Solved Problems
by Jyothsna V - Friday, 10 June 2011, 11:10 PM
  TG Sir,

Can u please explain the relation u established between d and x in the first question more clearly

Regards,
Jyothsna
Re: Time, Speed, Distance and Work- Solved Problems
by neha lahoti - Sunday, 26 June 2011, 09:44 AM
  Please help me with this problem:

In a kilometer race, Ram beats Shyam by one minute and Shyam beats Tarun
by 30 seconds. If Ram beats Tarun by 250m in the same race. Find the
time taken by Ram to run the race (in seconds).

ans; 270
Re: Time, Speed, Distance and Work- Solved Problems
by neha lahoti - Sunday, 26 June 2011, 11:50 AM
  Please tell me where i am wrong in the below solution:?
Also, the common question:

a car had to travel a total distance of 600 km. after travelling a part of the distance, it developed an engine problem. It travelled the remaining distance at 4\5 of the speed.It arrived an hour late.Had the engine problem occurred after it had travelled 150 more km  then it reached half an hour earlier.Find the distance it travelled without any problem.

Let it travel at S speed and the distance be D from where it broke down.
so s/(4/5s)=t+1\t =>t=4 hrs
so now
D-150\D=(t+1\2)\t+1
Re: Time, Speed, Distance and Work- Solved Problems
by TG Team - Tuesday, 28 June 2011, 05:33 PM
 
Hi Neha smile

That's a very easy question. Just see that if Ram takes 't' minutes to finish 1km (1000 m), then Shyam takes 't+1' and Tarun takes 't+1.5' minutes respectively.

Also it is given that Ram beats Tarun by 250 m i.e. Tarun can travel the remaining 250 m in 1.5 m i.e. 90 seconds. So Tarun must have taken 3*90 = 270 seconds to travel 3*250m = 750m distance in the same time in which Ram has travelled the complete distance of 1km = 1000m.

So answer is 270 seconds. smile

Kamal Lohia
Re: Time, Speed, Distance and Work- Solved Problems
by Anchit Tahlani - Thursday, 11 August 2011, 05:59 PM
 

HI sagar,

Ans=30

since men required:

total work= 20X16X10 MDH

New total work= (13/4)X20X16X10= 13X50X16

since wd by 20 men or 25 women or 30 boys is same

m:w:b = 4:5:6

Therefore, 10 women = 8 men & 18 boys= 12 men, so 20 men are there

(20+ExtraMen) X 26days X 8hrs = 13 X 50 X 16 mendayhrs

ExtraMen=30

 

Re: Time, Speed, Distance and Work- Solved Problems
by monika sharma - Sunday, 15 July 2012, 06:58 AM
  Thank TG,

For such a useful article.But i think,In the 7th question, 2nd method of solution, the value of v should be 60. so that when we multiply v and t then answer will be 300.

U r Genius.... approve
Re: Time, Speed, Distance and Work- Solved Problems
by Faiyaz Mohammad - Tuesday, 31 July 2012, 03:46 PM
 

Hi TG,

'Dog for a Walk' Problem can be easily solved using options..similar technique which you used in one of the articles 'Shortcut for quants'.

For the First meeting point the ratios of thier speeds will be equal to ratios of their distances covered. If V be the speed of Dog then

4/v = d1/(625+625-d1)---->1

where d1 is the distance travelled by the man till the first meeting point.

Now lets check the options of the second question -

for distance covered by dog to be 1000 -- d1 has to be 250. substituting in 1 we get 4/v = 250/1000

v = 16 which is among the options in the first question. Similarly we can see that none of the other options satisfy. smile

Btw why TG.com is so descolated? Guys Lets activate smile

Faiyaz

Re: Time, Speed, Distance and Work- Solved Problems
by kirti vardhan - Tuesday, 31 July 2012, 04:20 PM
  can anyone please explain me the wall problem here in the article..
Re: Time, Speed, Distance and Work- Solved Problems
by Faiyaz Mohammad - Wednesday, 1 August 2012, 12:49 PM
 

Hi Kirti,

Concept is simple. the wall will grow only when Added lengh is more than that of falling. lets take the wall Length to be 8m. Then 1/8 length = 1 m is build every day and 20% of the length build till that day is demolished.

So when the length of the wall reaches 5m, at the end of the day the wall demolised will be 20% of 5m = 1m which is the length build on that day.

so new wall length will be 4m. now whenever 1m is added 1m is demolished. hence the wall remains at 4m.

i hope its clear smile

 

Faiyaz

Re: Time, Speed, Distance and Work- Solved Problems
by Vaibhavi Negi - Wednesday, 13 February 2013, 01:14 AM
  I have a query
Raj and Neetu leaves form college together to their home.Raj travles on Cycle and Neetu walks on foot with different speeds.Raj travels towards their home and return back to neetu. After third round they walks 27m together with same speed.
If speed of Neetu is 4km/h duirng her walk and The distance between their house and college Gate is 125 then Find Speed of Raj.
Re: Time, Speed, Distance and Work- Solved Problems
by Total Gadha - Monday, 18 February 2013, 08:32 PM
  Vaibhav,

The question is not clear. How come they are 'walking together' in the third round? Isn't Raj traveling on bicycle? And what does 'third round' mean?
Re: Time, Speed, Distance and Work- Solved Problems
by sam banda - Wednesday, 5 June 2013, 08:07 PM
  I have a doubt in 1st question,as explained if A travels d+3x/2 and B travels 2d,that means distance between A and B is d+3x/2+2d i.e 3d+3x/2 whereas it actually is 3d+x..Can anyone please explain thi to me :-O
Re: Time, Speed, Distance and Work- Solved Problems
by Roshan Kumar - Monday, 17 June 2013, 12:51 PM
  plz provide the solution for this question
Re: Time, Speed, Distance and Work- Solved Problems
by debaditya khan - Monday, 17 June 2013, 03:13 PM
  let asssume the distance between college & home is = d
when they meet first time let the distance from home to neetu is= x
then distance covered by raj=(d+x)
distance covered by neetu= (d-x)
if their speed is v1 & v2 respectably
then v1/v2=k=(d+x)/ (d-x)
or, x=d(k-1)/(k+1)
for third round it will be {d(k-1)/(k+1)}^3 = 27=3^3
or k=4

therefore speed of raj is=4*4= 16 km/hr
Re: Time, Speed, Distance and Work- Solved Problems
by ankit SAHAY - Monday, 9 September 2013, 10:32 PM
  need help understanding this question pls respond:

A starts at a point P, on a circular track of length 10 km, at 6 am and runs at a speed 3u km/hr in the clockwise direction. B starts running at a speed of 2u km/hr from Q, the point diametrically opposite to P at 6:05 am, in the opposite direction. If u is less than 30, at how many distinct points do A and B meet on the track?

a)3
b)5
c)6
d)cannot be determined
Re: Time, Speed, Distance and Work- Solved Problems
by Hemlata Tiwari - Saturday, 3 May 2014, 08:09 PM
  Answer for the 4th question is 25kmph

let usual speed= 100 kmph and time = t
and distance = 100*t km ...(1)

In frst condition
new speed s1=125kmph
new time t1= t(usual time)+15/60
and distance = 125*(t+15/60) km ...(2)

And in second cndtn

new speed s2= 375/2kmph
new time t2= t-5/60
and distance = (375/2)*(t-5/60) km ...(3)

frmeq (2) & (3)
t = 1/4 hour

then frm eq(1)

distance = 100*1/4 = 25 kmph
Re: Time, Speed, Distance and Work- Solved Problems
by raghav saluja - Tuesday, 28 October 2014, 12:26 AM
  Can anyone help me with this Question??

Arun took part in a triathlon, an athletic event. he had to swim, run and bicycle to 10km , 24km and 30km respectively and return the same way.
Arun's average speed for the triathelon is 4 Km/h. he took a total of 4 min for swimming and 20 min for bicycling in the triathelon.
 His speed of running is :
a) 5km/min
b) 6km/min
c) 7.5km/min
d) 8/3 km/min

P.S. - I guess, this is a wrong Question.