Question

What percent of 80 is 8?

Answer 1

`10%`

Explanation:

Turn this word problem into an equation. Here are a couple hints to remember:

1. The word "is" means "equals", so wherever you see "is", use a `=` sign.
2. Likewise, the word "of" means "multiplication", so use a `xx` sign when you see that word.
3. Given variables to things you don't know. Since the percent is not known, give it the variable `x`.
4. A percent is a number over a hundred. Since the percent is not known, put `x` over 100: `x/100`

`stackrel(x/100)overbrace"What percent"stackrel(xx)overbrace"of"stackrel(80)overbrace"80"stackrel(=)overbrace"is"stackrel(8)overbrace"8"`

`x/100 xx 80 = 8`

`x/100 xx 80/1 = 8`

`uarr`(anything divided by 1 is itself, so putting 80 over 1 does not change it's value)

`(x xx 80)/(100 xx 1) = 8`

`(80x)/100 = 8`

`80x = 800`

`x = 10%`