Source: Official Guide for the GMAT 13th Ed. Problem Solving; #114 Official Guide for the GMAT 2015 14th Ed. Problem Solving; #114

3

In Country C, the unemployment rate among

In Country C, the unemployment rate among construction workers dropped from 16 percent on September 1, 1992, to 9 percent on September 1, 1996. If the number of construction workers was 20 percent greater on September 1, 1996, than on September 1, 1992, what was the approximate percent change in the number f unemployed construction workers over this period?

2 Explanations

2

Gravatar Mike McGarry, Magoosh Tutor

Dec 28, 2013 • Comment

2

Gravatar Lucas Fink, Magoosh Tutor

Since we're not given any concrete numbers here, only percents, we can plug in some numbers to help make this more workable.

Let's say there were 100 construction workers (including unemployed) in 1992. 16% of that 100 means there were 16 unemployed workers.

If the number of total workers increased by 20% in 1996, that means the total number of workers in 1996 was 120 (that's 120% of 100). If the unemployment rate was 9%, then there were .09*120 = 10.8 unemployed workers (this isn't really possible, but that's okay for now--we're only looking at percents, in the end).

So far, we have this:

Total 1992 workers: 100
Unemployed 1992 workers: 16
Total 1996 workers: 120
Unemployed 1996 workers: 10.8

Now we just need the percent change from 16 to 10.8. The difference is -5.2, so the percent change is -5.2/16 * 100

That's very close to -5/15, or - 1/3, so we can just estimate that this is about -33%. (D), -30% is closest.

Aug 12, 2013 • Comment

Add Your Explanation

You must have a Magoosh account in order to leave an explanation.

Learn More About Magoosh

Official GMAT Material

Official Guide for GMAT Review 2016

Official Guide for the GMAT 2015 14th Ed.

Official Guide for the GMAT 13th Ed.

Nova's GRE Prep

Official Guide for the GMAT 12th Ed.

Revised GRE PDF 2nd Ed.


Section 5.3 Problem Solving

Section 5.3 Problem Solving

Improve Your Score

Magoosh GMAT is an affordable online course for studying the GMAT.

Learn More About Magoosh

Share Post

Email

Facebook