315.5 is what percent of 405 - 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 405 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 405, so we can write it down as 100%=405.
4. We know, that x% equals 315.5 of the output value, so we can write it down as x%=315.5.
5. Now we have two simple equations:
1) 100%=405
2) x%=315.5
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%=405/315.5
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 315.5 is what percent of 405

100%/x%=405/315.5
(100/x)*x=(405/315.5)*x       - we multiply both sides of the equation by x
100=1.283676703645*x       - we divide both sides of the equation by (1.283676703645) to get x
100/1.283676703645=x
77.901234567901=x
x=77.901234567901

now we have:
315.5 is 77.901234567901% of 405