68 is what percent of 71?

1. We assume, that the number 71 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 71 is 100%, so we can write it down as 71=100%. 

4. We know, that x is 68% of the output value, so we can write it down as x=68%. 

5. Now we have two simple equations:

1) 71=100%

2) x=68%

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:
71/x=100%/68%

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 68% of 71

71/x=100/68
(71/x)*x=(100/68)*x       - we multiply both sides of the equation by x
71=1.4705882352941*x       - we divide both sides of the equation by (1.4705882352941) to get x
71/1.4705882352941=x 
48.28=x 
x=48.28

now we have: 
68% of 71=48.28