What Makes a Hard GMAT Question: Part 2

In part 2 of this series, we’ll look at another major criterion that determines the difficulty level of hard GMAT questions: Disguising the Mathematical Concept the Question is Addressing. As in part 1, I suggest that you attempt both questions first,…

Factoring Exponential Expressions

Most of the time on the GMAT, manipulations with exponents are fairly straightforward. Usually, you’ll see two terms with a common base, and you’ll be expected to divide or multiply those terms (such as: 25 / 23 or 35 x 38). However, when you get to some of the higher-level questions, you’ll be expected to handle situations in which…

If you’ve been studying for the GMAT, you’ve probably encountered situations that require knowledge of quadratic equations and how they work. In so doing, you’ve also probably memorized the following three equivalencies: (x + y)2 = x2 + 2xy + y2 (x – y)2 = x2 – 2xy + y2 (x – y)(x + y) = x2 – y2 Knowledge of these…

GMAT Data Sufficiency: Breaking Your Assumptions

One of the most widespread mistakes I see students make on Data Sufficiency concerns the information they consider when evaluating a statement. To properly determine whether a statement is sufficient, you must be focused on using only the information given. If, for example, a statement only tells you that -10 < x < 10, but says nothing else,…

Prime Factors on the GMAT

Some of the most common Number Properties questions on the GMAT require you to recognize how many times a certain number is a factor of another number. For example “If 81 =3x, then x = ?” Most students answer this question correctly because they recognize that 81 can be re-written as 34, thus making the answer…