BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Right triangle ABC is to be drawn

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Moderator
Posts: 7187
Joined: Thu Sep 07, 2017 4:43 pm
Followed by:23 members

Right triangle ABC is to be drawn

by BTGmoderatorDC » Mon Jan 08, 2018 5:18 pm
Right triangle ABC is to be drawn in the xy-plane so that the right angle is at A and AB is parallel to the y-axis. If the x- and y-coordinates of A, B, and C are to be integers that are consistent with the inequalities -6 ≤ x ≤ 2 and 4 ≤ y ≤ 9 , then how many different triangles can be drawn that will meet these conditions?

A. 54
B. 432
C. 2,160
D. 2,916
E. 148,824

I'm confused how to set up the formulas here. Can any experts help?

OA C
Top
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 228
Joined: Thu Apr 20, 2017 1:02 am
Location: Global
Thanked: 32 times
Followed by:3 members
GMAT Score:770

by elias.latour.apex » Mon Jan 08, 2018 7:27 pm
Well, first we must determine how many possible starting points there are for the A. Since there are 9 possibilities for x, and 6 possibilities for y, there are 54 starting points for the triangle.

But don't think that (A) is the answer. That number is far too low. Once we have selected A, we can select choice C. It will have the same x, but a different y. Since there are 5 remaining possibilities for y (we used one for A) we can multiply 54 * 5 to get 270.

Then we will have to choose a location for B. But why bother? We can see that whatever number we pick, the answer will end in a 0, because any integer multiplied by 270 will end in zero. Don't waste time on math. Only answer choice (C) has the right characteristics.

Don't do math. Just pick the right answer and move on.
Elias Latour
Verbal Specialist @ ApexGMAT
blog.apexgmat.com
+1 (646) 736-7622
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Tue Jan 09, 2018 8:18 am
Here's a similar question to practice with: https://www.beatthegmat.com/a-right-tria ... 97187.html

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Post new topic Post Reply
• Page 1 of 1