13.8 is what percent of 138 - 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 138 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 138, so we can write it down as 100%=138.
4. We know, that x% equals 13.8 of the output value, so we can write it down as x%=13.8.
5. Now we have two simple equations:
1) 100%=138
2) x%=13.8
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%=138/13.8
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 13.8 is what percent of 138

100%/x%=138/13.8
(100/x)*x=(138/13.8)*x       - we multiply both sides of the equation by x
100=10*x       - we divide both sides of the equation by (10) to get x
100/10=x
10=x
x=10

now we have:
13.8 is 10% of 138