138.5 is what percent of 390 - 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 390 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 390, so we can write it down as 100%=390.
4. We know, that x% equals 138.5 of the output value, so we can write it down as x%=138.5.
5. Now we have two simple equations:
1) 100%=390
2) x%=138.5
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%=390/138.5
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 138.5 is what percent of 390

100%/x%=390/138.5
(100/x)*x=(390/138.5)*x       - we multiply both sides of the equation by x
100=2.8158844765343*x       - we divide both sides of the equation by (2.8158844765343) to get x
100/2.8158844765343=x
35.512820512821=x
x=35.512820512821

now we have:
138.5 is 35.512820512821% of 390