21.12 is what percent of 40 - step by step solution

To get the solution, we are looking for, we need to point out what we know.

1. We assume, that the number 40 is 100% - because it's the output value of the task.
2. We assume, that x is the value we are looking for.
3. If 100% equals 40, so we can write it down as 100%=40.
4. We know, that x% equals 21.12 of the output value, so we can write it down as x%=21.12.
5. Now we have two simple equations:
1) 100%=40
2) x%=21.12
where left sides of both of them have the same units, and both right sides have the same units, so we can do something like that:
100%/x%=40/21.12
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 21.12 is what percent of 40

100%/x%=40/21.12
(100/x)*x=(40/21.12)*x       - we multiply both sides of the equation by x
100=1.8939393939394*x       - we divide both sides of the equation by (1.8939393939394) to get x
100/1.8939393939394=x
52.8=x
x=52.8

now we have:
21.12 is 52.8% of 40