Step by step
The question
Question: 15 is 125% of what number?
125% of ? = 15
We write it like this: 125% of the number is 15.
15 is a part.
The whole number is what we want.
? = the whole number
Careful!
Many people work out 125% of 15.
But 15 is not the whole.
It is only 125% of it.
Careful: not 125% of 15 ✗
1 Write the percent as a fraction
Percent means out of 100.
So 125% is 125/100.
125% = 125100
125 and 100 can both be divided by 25.
So 125% is 5/4: 5 parts, when 4 parts make the whole.
= 125 ÷ 25100 ÷ 25 = 54
2 Draw the whole
3 Find one part
5 parts make 15.
So one part is 15 divided by 5.
That is 3.
1 part = 15 ÷ 5 = 3
Every part is 3.
4 Find the whole
The whole is 4 parts.
4 times 3 is 12.
4 parts = 4 × 3 = 12
So 15 is 125% of 12.
5 Check
Let's check: is 125% of 12 really 15?
125% is 5/4.
Of means times.
12 divided by 4 is 3.
5 times 3 is 15.
125% of 12 = 54 × 12 = 5 × 3 = 15 (12 ÷ 4 = 3)
We get 15.
So it is right!
Let's look back.
First: write the percent as a fraction.
Then: draw the whole.
Then: find one part.
Then: find the whole.
Last: check.
Answer
4 parts = 4 × 3 = 12