Practice GMAT Questions
We provide hundreds of world-class practice GMAT questions with detailed explanations,
study guides,
and a
GMAT practice test
for free so that anyone can succeed on the GMAT.

GMAT Practice Question (One of Hundreds)
If (2439 + 18z)(81-18z)(2715 - 9z) = 1, what is the value of z?
Correct Answer: D
How can the number 1 be written to have a base of 3 and an exponent?
- Rewrite the terms on the left-side with common prime bases.
(2439 + 18z)(81-18z)(2715 – 9z)
= (35(9 + 18z))(34(-18z))(33(15 – 9z))
= (345 + 90z)(3-72z)(3(45 – 27z))
- Simplify by combining terms with like bases.
(345 + 90z)(3-72z)(3(45 – 27z))
= 345 + 45 + 90z – 72z – 27z
= 390 -9z
- As a result of this simplification, the equation is much easier to deal with.
390 -9z = 1
- At this point, the problem may appear unsolvable as different bases and exponents exist. However, remember that any number raised to the 0th power is 1. Consequently, 1 can be rewritten as 30. The equation now reads:
390 -9z = 1
390 -9z = 1 = 30
- Since the bases are the same, you can set the exponents equal to each other. The equation becomes:
90 – 9z = 0
90 = 9z
z = 10
Practice Verbal Questions
The best way to achieve a good score on the GMAT is to master the content tested on the GMAT and practice it extensively. We sincerely believe anybody can score a 700 or higher with enough practice and study of the content tested by the GMAT. In order to help you achieve a high score, we are pleased to provide you with a series of high-quality GMAT sample questions and detailed explanations for free. Written by our staff, these questions have helped countless students achieve a top score. In addition, we provide a daily GMAT practice question RSS feed.