Data Sufficiency: Value of X

CAT 1993 Slot 1 · QA · Easy · QA

Given that XX and YY are non-negative. What is the value of XX?

I. 2X+2Y402X + 2Y \le 40 II. X2Y20X - 2Y \ge 20

  1. A.

    If the question can be answered with the help of statement I alone

  2. B.

    If the question can be answered with the help of statement II alone

  3. C.

    If both statement I and statement II are needed to answer the question

  4. D.

    If the question cannot be answered even with the help of both statements

Answer

C

Explanation

From Statement I: X+Y20X + Y \le 20. Alone insufficient. From Statement II: X2Y20X - 2Y \ge 20. Alone insufficient. Combining both: 2X+2Y402X + 2Y \le 40 and 2YX202Y \le X - 20. Since X,Y0X, Y \ge 0, adding X+Y20X + Y \le 20 and X2Y20X - 2Y \ge 20 yields 3Y0    Y=03Y \le 0 \implies Y = 0. Then X=20X = 20. Both statements together are sufficient.

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