31.15 is what percent of 400 - 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 400 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 400, so we can write it down as 100%=400.
4. We know, that x% equals 31.15 of the output value, so we can write it down as x%=31.15.
5. Now we have two simple equations:
1) 100%=400
2) x%=31.15
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%=400/31.15
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 31.15 is what percent of 400

100%/x%=400/31.15
(100/x)*x=(400/31.15)*x       - we multiply both sides of the equation by x
100=12.841091492777*x       - we divide both sides of the equation by (12.841091492777) to get x
100/12.841091492777=x
7.7875=x
x=7.7875

now we have:
31.15 is 7.7875% of 400