What is 21 percent of 87.5 - 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 87.5 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 87.5 is 100%, so we can write it down as 87.5=100%.
4. We know, that x is 21% of the output value, so we can write it down as x=21%.
5. Now we have two simple equations:
1) 87.5=100%
2) x=21%
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:
87.5/x=100%/21%
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for what is 21% of 87.5

87.5/x=100/21
(87.5/x)*x=(100/21)*x       - we multiply both sides of the equation by x
87.5=4.7619047619*x       - we divide both sides of the equation by (4.7619047619) to get x
87.5/4.7619047619=x
18.375=x
x=18.375

now we have:
21% of 87.5=18.375