25 is what percent of 1640 - 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 1640 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 1640, so we can write it down as 100%=1640.
4. We know, that x% equals 25 of the output value, so we can write it down as x%=25.
5. Now we have two simple equations:
1) 100%=1640
2) x%=25
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%=1640/25
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 25 is what percent of 1640

100%/x%=1640/25
(100/x)*x=(1640/25)*x       - we multiply both sides of the equation by x
100=65.6*x       - we divide both sides of the equation by (65.6) to get x
100/65.6=x
1.5243902439024=x
x=1.5243902439024

now we have:
25 is 1.5243902439024% of 1640