399.5 is what percent of 280 - 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 280 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 280, so we can write it down as 100%=280.
4. We know, that x% equals 399.5 of the output value, so we can write it down as x%=399.5.
5. Now we have two simple equations:
1) 100%=280
2) x%=399.5
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%=280/399.5
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 399.5 is what percent of 280

100%/x%=280/399.5
(100/x)*x=(280/399.5)*x       - we multiply both sides of the equation by x
100=0.7008760951189*x       - we divide both sides of the equation by (0.7008760951189) to get x
100/0.7008760951189=x
142.67857142857=x
x=142.67857142857

now we have:
399.5 is 142.67857142857% of 280