40 is what percent of 30.8 - 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 30.8 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 30.8, so we can write it down as 100%=30.8.
4. We know, that x% equals 40 of the output value, so we can write it down as x%=40.
5. Now we have two simple equations:
1) 100%=30.8
2) x%=40
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%=30.8/40
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 40 is what percent of 30.8

100%/x%=30.8/40
(100/x)*x=(30.8/40)*x       - we multiply both sides of the equation by x
100=0.77*x       - we divide both sides of the equation by (0.77) to get x
100/0.77=x
129.87012987013=x
x=129.87012987013

now we have:
40 is 129.87012987013% of 30.8