What is 8 percent of two hundred

1. We assume, that the number 200 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 200, so we can write it down as 100%=200. 
4. We know, that x% equals 8 of the output value, so we can write it down as x%=8. 
5. Now we have two simple equations:
1) 100%=200
2) x%=8
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%=200/8
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 8 is what percent of 200

100%/x%=200/8
(100/x)*x=(200/8)*x       - we multiply both sides of the equation by x
100=25*x       - we divide both sides of the equation by (25) to get x
100/25=x 
4=x 
x=4

now we have: 
8 is 4% of 200