What is 2.5 percent of 638.5 - 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 638.5 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 638.5 is 100%, so we can write it down as 638.5=100%.
4. We know, that x is 2.5% of the output value, so we can write it down as x=2.5%.
5. Now we have two simple equations:
1) 638.5=100%
2) x=2.5%
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:
638.5/x=100%/2.5%
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for what is 2.5% of 638.5

638.5/x=100/2.5
(638.5/x)*x=(100/2.5)*x       - we multiply both sides of the equation by x
638.5=40*x       - we divide both sides of the equation by (40) to get x
638.5/40=x
15.9625=x
x=15.9625

now we have:
2.5% of 638.5=15.9625