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Last Updated on May 9, 2023
GMAT OFFICIAL GUIDE DS –
Solution:
We are given three angles of a triangle, angles x, y, and z. Since the angles in a triangle sum to 180 degrees, we know:
x + y + z = 180
We need to determine the measure of angle z. Let’s isolate z in the above equation.
z = 180 – x – y
z = 180 – (x + y)
Thus, if we can determine the values of x and y or the value of x + y, we can determine the value of z.
Statement One Alone:
x + y = 139
Since x + y = 139, z = 180 – 139 = 41. Statement one alone is sufficient to answer the question. We can eliminate answer choices B, C, and E.
Statement Two Alone:
y + z = 108
Statement two alone is not enough information to determine the value of z since we can’t determine the value of y or the value of x + y.
Answer: A
