What is 4.2 percent of 639 - 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 639 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 639 is 100%, so we can write it down as 639=100%.
4. We know, that x is 4.2% of the output value, so we can write it down as x=4.2%.
5. Now we have two simple equations:
1) 639=100%
2) x=4.2%
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:
639/x=100%/4.2%
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 4.2% of 639

639/x=100/4.2
(639/x)*x=(100/4.2)*x       - we multiply both sides of the equation by x
639=23.809523809524*x       - we divide both sides of the equation by (23.809523809524) to get x
639/23.809523809524=x
26.838=x
x=26.838

now we have:
4.2% of 639=26.838