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

Redeem

Percentage Decrease

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 158
Joined: Mon Nov 02, 2009 5:49 pm
Thanked: 2 times
Followed by:3 members

Percentage Decrease

by tonebeeze » Tue Mar 15, 2011 8:53 am
If the length and width of a rectangular diagram 12 inches by 8 inches are to be reduced by the same percent so that the diagram will exactly fit into a rectangular space 4.5 inches by 3 inches, by what percent should the dimensions by reduced?

a. 25%
b. 37.5%
c. 62.5%
d. 75%
e. 87%

Any good study tips regarding mastering percentage increase and decrease problems?

OA = C
Top
Source: — Problem Solving |
User avatar
Legendary Member
Posts: 1101
Joined: Fri Jan 28, 2011 7:26 am
Thanked: 47 times
Followed by:13 members
GMAT Score:640

by HSPA » Tue Mar 15, 2011 9:01 am
How to avoid chosing option B in such questions... I mean when doing quick 4.5 is 37.5% of 12... so in a hurry I chose B... but question asks by what percent it shall be reduced ... 62.5
Top
Master | Next Rank: 500 Posts
Posts: 158
Joined: Mon Nov 02, 2009 5:49 pm
Thanked: 2 times
Followed by:3 members

by tonebeeze » Tue Mar 15, 2011 9:06 am
That's exactly what I did. When you look at the problem, the answer is intuitively easy, but the language of the problem is tricky. I missed these problems with minor careless errors.
Top
User avatar
Senior | Next Rank: 100 Posts
Posts: 74
Joined: Fri Dec 17, 2010 12:37 pm
Location: Munich
Thanked: 3 times

by garuhape » Tue Mar 15, 2011 9:07 am
In this case you have to figure out which of the two sides you have to reduce more.

1. 12inches are reduced to 4.5 inches. Therefore, the new side is only 4.5/12*100% which is (4.5*8.5)/100 = 38.25%

2. 8 inches are reduced to 3 inches. Therefore, you have to multiply both by 12.5 to get % since 8*12.5=100. The result is 37.5/100 which is 37.5%. That's why it has to be reduced by 100%-37.5% which is 62.5%
Top
Post new topic Post Reply
• Page 1 of 1