22.4 is what percent of 640 - 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 640 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 640, so we can write it down as 100%=640.
4. We know, that x% equals 22.4 of the output value, so we can write it down as x%=22.4.
5. Now we have two simple equations:
1) 100%=640
2) x%=22.4
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%=640/22.4
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 22.4 is what percent of 640

100%/x%=640/22.4
(100/x)*x=(640/22.4)*x       - we multiply both sides of the equation by x
100=28.571428571429*x       - we divide both sides of the equation by (28.571428571429) to get x
100/28.571428571429=x
3.5=x
x=3.5

now we have:
22.4 is 3.5% of 640