309.99 is what percent of 399 - 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 399 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 399, so we can write it down as 100%=399.
4. We know, that x% equals 309.99 of the output value, so we can write it down as x%=309.99.
5. Now we have two simple equations:
1) 100%=399
2) x%=309.99
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%=399/309.99
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 309.99 is what percent of 399

100%/x%=399/309.99
(100/x)*x=(399/309.99)*x       - we multiply both sides of the equation by x
100=1.2871382947837*x       - we divide both sides of the equation by (1.2871382947837) to get x
100/1.2871382947837=x
77.691729323308=x
x=77.691729323308

now we have:
309.99 is 77.691729323308% of 399