Question: 3x-5

Comment on 3x-5


I was able to solve using the approach however I first tried solving using: 2(3x-5)+2(x-15)=360 and got x=50

How come this doesn't work?
gmat-admin's picture

That's the right idea, but you have (x-15), when it should by (x+15)

Here it is given x+15. x-15 will give wrong answer.

Hey Brent, what's your opinion on redrawing the figures? Some questions take a bit of time to redraw so there's the downside of losing time, but it seems to help a lot in being able to label various parts of the diagram.

Any rule of thumb for redrawing?
gmat-admin's picture

I think redrawing the figures is almost always a good idea, especially if there are many missing angles and lengths in the figure. That said, if there's little information that can be added to the diagram, then I wouldn't bother.

For example, if a diagram consists of a right triangle with the lengths of two sides given, and your task is to determine the length of this missing side, then there wouldn't be much value in redrawing the triangle.


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 a GMAT expert will answer it as fast as humanly possible.

Free “Question of the Day” emails!