## Previous Year Paper

### CAT-2007-Previous Years Paper

Question
24 out of 25

The average weight of a class of 100 students is 45 kg. The class consists of two sections, I and II, each with 50 students. The average weight, WI, of Section I is smaller than the average weight, WII, of Section II. If the heaviest student, say Deepak, of Section II is moved to Section I, and the lightest student, say Poonam, of section I is moved to section II then the average weights of the two sections are switched, i.e., the average weight of Section I becomes WIIand that of Section II becomes WI. What is the weight of Poonam?

A: WII– WI= 1.0

B: Moving Deepak from Section II to I (without any move from I to II) makes the average weights of the two sections equal.

 A If the question can be answered using A alone but not using B alone. B If the question can be answered using B alone but not using A alone. C If the question can be answered using A and B together, but not using either A or B alone. D If the question cannot be answered even using A and B together.
Ans. C

WI= Average weight of Section I

WII= Average weight of section II

WI+ WII= 90 where W1II

Let weight of Deepak and Poonam be D and P kgs respectively

and

⇒ 50 (WII– WI) = D – P

Using Statement A alone:

50 × 1 = D – P

Thus, D and P can take various values.

So, statement A alone

50 × 1 = D – P (i)

Thus, D and P can take various values.

Hence, Stat. A alone is not sufficient.

Using Stat. B alone:

(ii)

Since values of WIand WIIare not known

We cannot find the value of D.

Combining both the statements,

Values of WIand WIIcan be found and hence value of D and P can be found, using (i) and (ii).