12.8 is what percent of 18 - 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 18 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 18, so we can write it down as 100%=18.
4. We know, that x% equals 12.8 of the output value, so we can write it down as x%=12.8.
5. Now we have two simple equations:
1) 100%=18
2) x%=12.8
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%=18/12.8
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 12.8 is what percent of 18

100%/x%=18/12.8
(100/x)*x=(18/12.8)*x       - we multiply both sides of the equation by x
100=1.40625*x       - we divide both sides of the equation by (1.40625) to get x
100/1.40625=x
71.111111111111=x
x=71.111111111111

now we have:
12.8 is 71.111111111111% of 18