Question

What percent is 28 of 70?

Answer 1

The answer is 40%
You assume that the number 70 is 100% because it's the output value of the task, X is what you will be looking for
100%=70 So we know that x% equals 28 of the output value, so x%=28
Which gives you two simple equations
1. 100%=70
2. x%=28 
Where both sides of them have the same unites, both right sides have the same unites, so we can do something like 100%/x%=70/28 and then you solve the equation to get what you are looking for

(100/x)*x=(70/28)*x - you multiply both sides by X
100=2.5*x - you divide both sides of the equations by (2.5) to get x
100/2.5=x
40=x so X equals 40

Answer 2

To find the percentage of 28 from 70:

28/70=0.4

0.4=40%