CAT 1999 | Question: 162

Question

The question is followed by two statements I and II.

Mark

• A. if the question can be answered by any one of the statements alone, but cannot be answered by using the other statement alone.
• B. if the question can be answered by using either statement alone.
• C. if the question can be answered by using both the statements together, but cannot be answered by using either statement alone.
• D. if the question cannot be answered even by using both the statements together.

 

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?

1. A mathematician can never add two numbers correctly, but can always add three numberscorrectly.
2. When a mathematician makes a mistake in a sum, the error is $+1$ or $–1.$

Answer 1

I)A mathematician can never add two numbers correctly, but can always add three numberscorrectly.

Here A got incorrect answer for 2 numbers ,So, A is mathemetician

B got incorrect result with 3 numbers - B is not a mathematician

C got correct result with 2 numbers - C is not a mathematician

Ans A) if the question can be answered by any one of the statements alone, but cannot be answered by using the other statement alone.

Comments

B and Care not mathematicians. But there is no roof of A being a mathematician- even others can add 2 numbers wrong. So, answer must be D.