If x, y, and z are all nonzero numbers, and x = y + z, which of the following is equal to 1?

[BTGModeratorVI]

If x, y, and z are all nonzero numbers, and x = y + z, which of the following is equal to 1?

(A) (y – z)/x
(B) (y – x)/z
(C) (z – x)/y
(D) (z – y)/x
(E) (x – z)/y

Answer: E
Source: Veritas Prep

[Brent@GMATPrepNow]

If x, y, and z are all nonzero numbers, and x = y + z, which of the following is equal to 1?

(A) (y – z)/x
(B) (y – x)/z
(C) (z – x)/y
(D) (z – y)/x
(E) (x – z)/y

Answer: E
Source: Veritas Prep

NOTE: this is one of those questions that require us to check/test each answer choice. In these situations, always check the answer choices from E to A, because the correct answer is typically closer to the bottom than to the top.

For more on this strategy, see my article: https://www.gmatprepnow.com/articles/han ... -questions

Given: x = y + z

E) (x – z)/y
Replace x with y + z to get: (y + z - z)/y
Simplify: y/y
This definitely equals 1.

Answer: E

Cheers,
Brent