Can someone solve this problem for me???

Problem Solving — algebra and arithmetic (GMAT Focus Edition)
This topic has expert replies
Source: — Quantitative Reasoning |

User avatar
Legendary Member
Posts: 1309
Joined: Mon Apr 04, 2011 5:34 am
Location: India
Thanked: 310 times
Followed by:123 members
GMAT Score:750

by cans » Mon May 30, 2011 12:15 pm
(20-n)+n+(18-n)=25
well you can write it as:- 20-n+n+18-n=25
20+18-n=25
38-n=25
38-25=n
or n=13

User avatar
Legendary Member
Posts: 1255
Joined: Fri Nov 07, 2008 2:08 pm
Location: St. Louis
Thanked: 312 times
Followed by:90 members

by Tani » Mon Jun 06, 2011 9:33 am
The formula is

G1 + G2 - B + N = T

(The total in group one), plus (the total in group two) minus (those items in both groups one and group two - i.e.those items that would have been double-counted) plus (those items not included in any group) equals the total.

With this problem you get 20 + 18 - n + 0 = 25 Therefore n = 13.
Tani Wolff