Question

In a city of 56,000 people, there are 21,000 people under 25 years of age. What percent of the population is under 25 years of age?

Answer 1

37.5

Explanation:

So whenever you want to find "x" percent of a number, you just do:
`(x)/(100) * n = \text{x\% of n}`. You're essentially converting the percentage to it's decimal value by dividing by 100.

Given this information, we're solving for x, instead of x% of n. In this case n = 56,000, and x% of 56,000 is 21,000

`(x)/(100) * 56000 = 2100`

Divide both sides by 56,000

`(x)/(100) = (21,000)/(56,000)`

Multiply both sides by 100

`x = 100((21,000)/(56,000))`

Simplify:

`x = 37.5\%`

This can be generally thought of as:

`x=100((part)/(whole))`

where part = partial amount, or how much is after finding what x% is of the whole amount, but in this case we know what it is, we just don't know what the "x" percent is.