321.5 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 321.5 of the output value, so we can write it down as x%=321.5.
5. Now we have two simple equations:
1) 100%=390
2) x%=321.5
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%=390/321.5
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 321.5 is what percent of 390

100%/x%=390/321.5
(100/x)*x=(390/321.5)*x       - we multiply both sides of the equation by x
100=1.2130637636081*x       - we divide both sides of the equation by (1.2130637636081) to get x
100/1.2130637636081=x
82.435897435897=x
x=82.435897435897

now we have:
321.5 is 82.435897435897% of 390