What is 31 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 31% of the output value, so we can write it down as x=31%.
5. Now we have two simple equations:
1) 639=100%
2) x=31%
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%/31%
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 31% of 639

639/x=100/31
(639/x)*x=(100/31)*x       - we multiply both sides of the equation by x
639=3.2258064516129*x       - we divide both sides of the equation by (3.2258064516129) to get x
639/3.2258064516129=x
198.09=x
x=198.09

now we have:
31% of 639=198.09