Question: What Must Be True?

Comment on What Must Be True?

Regardless of p, assuming q is even or odd then:
q-1 or q-2: one of the two has to be even.
Thus, the result must be even.

Is this correct?
gmat-admin's picture

That is correct, devroy. Great work.

Hi, quick question; the expression you evaluated to 0, are you using the foil method? :S is there a quick way you are doing it? thanks, ps love the site.
gmat-admin's picture

I'm just plugging in 2 for an even value and 1 for an odd value, and then performing the necessary calculations.

HOWEVER, once I see that one of the pieces in the product equals zero, I immediately know that the final result will equal zero.

For example, when we plug in 2 for p and q in the first expression, we get 2(2-2)(2-1)
Once I recognize that 2-2 = 0, then we have 2(2-2)(2-1) = 2(ZERO)(2-1), which means the final product will be zero.

understood. thanks :)

Add a comment

Office Hours

Have questions about your preparation or an upcoming test? Need help modifying the Study Plan to meet your unique needs? No problem. Just book a Skype meeting with Brent to discuss these and any other questions you may have. 

Change Playback Speed

You have the option of watching the videos at various speeds (25% faster, 50% faster, etc). To change the playback speed, click the settings icon on the right side of the video status bar.

Have a question about this video?

Post your question in the Comment section below, and I’ll answer it as fast as humanly possible.

Free “Question of the Day” emails!