Question

How to find percent wholes?

30% of what number is 15?
Please explain!
TYSM!

Answer 1

`50`

Explanation:

We will turn this into an equation so that we can solve it easier. Here are some tips to start:

1. The word of means multiplication, so you can put a `xx` sign wherever you see the word "of".
2. The word is means equals, so you can use a `=` sign when you see this word.
3. `30%` is the same as `30/100` as a fraction or `0.3` as a decimal. I will be using the fraction in the equation.
4. Give things variable so that you can solve them easier! I'm going to give "what number" the variable `x`:

`stackrel(30/100)overbrace(30%)stackrel(xx)overbrace"of"stackrel(x)overbrace"what number"stackrel(=)overbrace"is"stackrel(15)overbrace"15"`?

`30/100 xx x = 15`

`30/100 xx x/1 = 15` (remember that anything divided by `1` is itself, so putting `x` over `1` doesn't change it's value)

`(30x)/100 = 15`

`(30x)/cancel100cancel100 = 15 xx 100`

`30x = 1500`

`x = 50`

So `30%` of `color(blue)50` is `15`.