CAT 1997 — QA Question 46
Answer the next 2 questions based on the following information.
A thief, after committing the burglary, started fleeing at 12 noon, at a speed of 60 km/hr. He was then chased by a policeman X. X started the chase, 15 min after the thief had started, at a speed of 65 km/hr.
Direction: Each of these items has a question followed by two statements, I and II. Mark the answer
1. if the question can be answered with the help of one statement alone.
2. if the question can be answered with the help of any one statement independently.
3. if the question can be answered with the help of both statements together.
4. if the question cannot be answered even with the help of both statements together.
What is the value of a3 + b3 ?
I. a2 + b2 = 22
II. ab = 3
Answer & solution
Answer: 4
a3 + b3 = (a + b)(a2 + b2 – ab). Combining statements I and II, we get the value of (a + b) = √28 or –√28. Since we do not have the unique value of (a + b), we cannot get the unique answer a3 + b3.