Source: Official Guide Revised GRE 2nd Ed. Part 9; Section 6; #21

3

# Of the people in a certain survey

Of the people in a certain survey 58 percent were at most 40 years old and 70 percent were at most 60 years old. If 252 of the people in the survey were more than 40 years old and at most 60 years old, what was the total number of people in the survey? 1,900, 2,100, 2,400, 2,700, 3,000

### 2 Explanations

1

Abhinav Shahu

58% people <= 40 years old -->> 42% people > 40 years old

70% people <= 60 years old

So 40 years old < % people <= 60 years old
= 70 - 42 = 28%

Is this calculation incorrect?

Feb 3, 2017 • Comment

Hi Abhinav,

I'm not sure where you're getting the 42% of people.

The important information we have is that:

70% are between 0 and 60 years
58% are between 0 and 40 years

That means that (70% - 58%) are between 40 and 60 years, or 12%.

We know that 252 people are between 40 and 60, so 12% of the total is 252.

We can use that information to solve for the total, which gives us 2100.

Does that make sense?

2

Chris Lele

Dec 8, 2012 • Comment