39 is what percent of 215 - 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 215 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 215, so we can write it down as 100%=215.
4. We know, that x% equals 39 of the output value, so we can write it down as x%=39.
5. Now we have two simple equations:
1) 100%=215
2) x%=39
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%=215/39
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 39 is what percent of 215

100%/x%=215/39
(100/x)*x=(215/39)*x       - we multiply both sides of the equation by x
100=5.51282051282*x       - we divide both sides of the equation by (5.51282051282) to get x
100/5.51282051282=x
18.1395348837=x
x=18.1395348837

now we have:
39 is 18.1395348837% of 215