
Three professors A, B and C are separately given three sets of numbers to add. They were expected to find the answers to 1 + 1, 1 + 1 + 2, and 1 + 1 respectively. Their respective answers were 3, 3 and 2. How many of the professors are mathematicians.
A. A mathematician can never add two numbers correctly, but can always add three numbers correctly.
B. When a mathematician makes a mistake in a sum, the error is + 1 or 1.
options:
1. only A is mathematician
2. data not sufficient
3. A and B are mathematicians
4. None of above 