21.45 is what percent of 30 - 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 30 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 30, so we can write it down as 100%=30.
4. We know, that x% equals 21.45 of the output value, so we can write it down as x%=21.45.
5. Now we have two simple equations:
1) 100%=30
2) x%=21.45
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%=30/21.45
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 21.45 is what percent of 30

100%/x%=30/21.45
(100/x)*x=(30/21.45)*x       - we multiply both sides of the equation by x
100=1.3986013986014*x       - we divide both sides of the equation by (1.3986013986014) to get x
100/1.3986013986014=x
71.5=x
x=71.5

now we have:
21.45 is 71.5% of 30