Data Sufficiency

This is a REALLY hard question. If you see something like this on the test, be happy, even if you don't get it right!

Yes, the wording is a bit tricky and, yes, you can sometimes get similar wording on the real test. Most of the time the wording is fairly straightforward but sometimes on the hardest questions, if you miss even a single word, it will change the whole problem.

For example, check out this OG problem (10th edition, PS #284):

On a certain road, 10 percent of the motorists exceed the posted speed limit and receive speeding tickets, but 20 percent of the motorists who exceed the posted speed limit do not receive speeding tickets. What percent of the motorists on that road exceed the posted speed limit?

(A) 10.5 %
(B) 12.5 %
(C) 15 %
(D) 22 %
(E) 30 %

When I give this one in class, the vast majority get it wrong the first time. Once they know how to do it, though, they realize the catch, and they realize they need to REMEMBER that catch so that they won't make the same mistake when they see a problem of this type again. The key is to learn the setup so that you can avoid the trap the next time.

(I'll post the OA down below in a separate post for people who want to try it without looking at the answer.)

The answer to the above PS question is B. The answer is NOT E, though most people pick it (even people who learn our double-set matrix method for doing this problem). Why? The wording. (What's the key word?)

I won't put an explanation up yet - play with it.