Question

Use the appropriate form of the percentage formula.30% of what number is 21?

Answer 1

If 30% of a number x is equal to 21, then x is to 100% as 21 is to 30%:

`(x)/(100)=(21)/(30)`

Solve for x:

`x=(21)/(30)*100=70`

Then, 30% of 70 is 21.

Therefore, the answer is 70.