We cover every section of the GMAT with in-depth lessons, 5000+ practice questions and realistic practice tests.

## Up to 100+ points GMAT score improvement guarantee

### The best guarantee you’ll find

Our Premium and Ultimate plans guarantee up to 100+ points score increase or your money back.

## Master each section of the test

### Comprehensive GMAT prep

We cover every section of the GMAT with in-depth lessons, 5000+ practice questions and realistic practice tests.

## Schedule-free studying

### Learn on the go

Study whenever and wherever you want with our iOS and Android mobile apps.

# POE: Overview

The national gross product (NGP) of Andalasia has decreased by 25%. Due to the ongoing war with Actasia, the NGP has decreased by an additional 10%. By approximately what percent would the NGP now have to be increased in order to restore it to its original amount?

Incorrect.

[[snippet]] GMAC got you this time. You must have tried real numbers, but the problem deals with percents. POE and move on.

Incorrect.

[[snippet]] A common mistake is to add up all the percents in the problem, without considering the original amount. In this question, the NGP decreased by 25% and then by an additional 10%. Adding these percentages ($$25\%+10\%=35\%$$) leads to this incorrect answer choice. POE and move on.

Correct.

[[snippet]]

Since the NGP is not given, plug in your own number. The perfect number to use with percents is 100. So in this case, $$\mbox{NGP} = 100$$. First we deduct 25% to get $$\mbox{NGP}=75$$. Then we deduct 10% of that to get $$\mbox{NGP} = 67.5$$. In order to restore the NGP to its original amount, Andalasia needs to add 32.5 to the current NGP. That's usually where most test takers fail. Reread the question. It's about the percent increase rather than about real numbers. Use the percent change formula to help you. >$$\displaystyle \mbox{Percent Change}=\frac{\mbox{Difference}}{\mbox{Original}}\cdot100$$ >$$\displaystyle \mbox{Percent Change}=\frac{32.5}{67.5}\cdot100$$ Such messy numbers can make you weep! Ballpark to save time and careless errors. >$$\displaystyle \frac{32.5}{67.5}\approx\frac{33}{66}=\frac{1}{2}$$ That's about 50%, which is why 48% is the best answer.

Incorrect.

[[snippet]] A common mistake is to add up all the percents in the problem, without considering the original amount. In this question, the NGP decreased by 25% and then by an additional 10%. Adding these percentages ($$25\%+10\%=35\%$$) leads to this incorrect answer choice. POE and move on.

Incorrect.

[[snippet]] GMAC got you this time. You must have tried real numbers, but the problem deals with percents. POE and move on.
32.5%
35%
48%
65%
67.5%