GMAT Math: You always have a choice
In every GMAT class I teach for Kaplan, I am always asked the same questions on the first day. “How am I supposed to handle data sufficiency questions?” “I have not done math in five (or ten or twenty) years, will I be ok on the GMAT?” And, “Can you explain how to do combinations and probability questions?” After answering these – “Use Kaplan’s method,” “Yes, with plenty of practice,” and “We will cover that in a later session, but it really is not as important as students make it out to be” – one of the students, usually sitting in the back of the classroom will raise his or her hand. After being called on, he or she states, with a clear bit of frustration in his or her voice, “I can get the problems right when I have an unlimited amount of time, but I cannot get them in the two minutes allotted by the GMAT.”
But that students frustration soon eases when I explain the key to completing GMAT math problems within the two minute time-frame: choose an approach. Not use an approach. Choose an approach.
Every GMAT problem can be handled in at least two, but usually more, ways. All of the approaches will eventually lead to the correct answer, but only one of them will get the test taker there in less than 120 seconds. And the real secret of the GMAT, is that it is not only trying to test math ability. Sure, math knowledge is a prerequisite to doing well on test day, but that alone is not enough. GMAT problems are designed to reward the student that considers all of the possible ways to approach a problem and then selects the one that is the most effective at reaching the correct answer in less than two minutes.
So, next time you do a GMAT practice problem, do not just start solving using the first method of which you think. Take a few seconds, consider your options and be proactive -- choose the best approach in order to maximize your time (and ultimately your score).