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

Redeem

Percentages

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 328
Joined: Thu Aug 07, 2008 5:25 pm
Location: Philadelphia
Thanked: 4 times
GMAT Score:550

Percentages

by Abdulla » Fri Dec 12, 2008 2:59 pm
A room contains 160 people, 15 percent of whom are women. A group of people, 30 percent of whom are women, leaves the room. Of the people remaining in the room, 10 percent are women. How many people left the room?

(A) 10
(B) 20
(C) 40
(D) 60
(E) 80

OA is C
Abdulla
Top
Source: — Problem Solving |
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Fri Dec 12, 2008 3:33 pm
15% of 160 is women = 24

Let x represent people who left the room(30% of these are women + 10% of 160-x are women and these both must add up to the original number of women we found above i.e. 24)

.30x + .10(160-x) = 24

x=40

C)
Top
Master | Next Rank: 500 Posts
Posts: 328
Joined: Thu Aug 07, 2008 5:25 pm
Location: Philadelphia
Thanked: 4 times
GMAT Score:550

by Abdulla » Fri Dec 12, 2008 3:44 pm
always your approach is better than the Official Explantion..

Thanks
Abdulla
Top
Master | Next Rank: 500 Posts
Posts: 154
Joined: Tue Aug 26, 2008 12:59 pm
Location: Canada
Thanked: 4 times

by canuckclint » Fri Dec 12, 2008 6:24 pm
Found a good way to solve this algebraically.

Let x be people who left the room, y of which are women.
y/x = 30/100 --30% who left the room are women
(24-y)/(160-x) = 10/100 --people left in the room 10% are women

2400 - 100y = 1600 - 10x
800 = 100y - 10x
800 = 100(x*30/100) - 10x
800 = 20x
x = 40
Top
Post new topic Post Reply
• Page 1 of 1