Jeff Miller

GMAT OFFICIAL GUIDE DS – What is the value of x+y…

What is the value of x+y…

Solution:

We need to determine the value of x + y in the given figure. Let’s start by sketching the figure.

In analyzing the angles in the figure, we must remember that the sum of the exterior angles of any polygon is 360°. Thus, we can say that x + y + w + z = 360 since these four angles represent the four exterior angles of the four-sided polygon in our diagram. Furthermore, since x + y = 360 – (w + z), if we can determine the value of w + z, we can determine x + y.

Statement One Alone: 

w = 95

Only knowing the value of w is not enough information to determine x + y. We can eliminate answer choices A and D.

Statement Two Alone: 

z = 125

Only knowing the value of z is not enough information to determine x + y. We can eliminate answer choice B.

Statements One and Two Together: 

Using statements one and two we see that z + w = 220.  Thus, x + y = 360 – 220 = 140.

Answer: C

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