Answer:
75% of 16=12
Explanation:
1. We assume, that the number 16 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 16 is 100%, so we can write it down as 16=100%. 
4. We know, that x is 75% of the output value, so we can write it down as x=75%. 
5. Now we have two simple equations: 
1) 16=100% 
2) x=75% 
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: 
16/x=100%/75% 
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 75% of 16 
 
16/x=100/75 
(16/x)*x=(100/75)*x - we multiply both sides of the equation by x 
16=1.33333333333*x - we divide both sides of the equation by (1.33333333333) to get x 
16/1.33333333333=x 
12=x 
x=12 
 
now we have: 
75% of 16=12