What is 18 percent of 639.5 - 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 639.5 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 639.5 is 100%, so we can write it down as 639.5=100%.
4. We know, that x is 18% of the output value, so we can write it down as x=18%.
5. Now we have two simple equations:
1) 639.5=100%
2) x=18%
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:
639.5/x=100%/18%
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 18% of 639.5

639.5/x=100/18
(639.5/x)*x=(100/18)*x       - we multiply both sides of the equation by x
639.5=5.5555555555556*x       - we divide both sides of the equation by (5.5555555555556) to get x
639.5/5.5555555555556=x
115.11=x
x=115.11

now we have:
18% of 639.5=115.11