Question

120 is what percent of 60

Answer 1

To solve this problem lets assume, that the number 60 is 100% - because it's the output value of the task. We assume, that x is the value we are looking for. If 100% equals 60, so we can write it down as 100%=60. We know, that x% equals 120 of the output value, so we can write it down as x%=120. Now we have two simple equations:
1)100%=60
2) x%=120
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%=60/120.
Now we just have to solve the simple equation, and we will get the solution we are looking for.

Solution for 120 is what percent of 60

100%/x%=60/120
(100/x)*x=(60/120)*x       - we multiply both sides of the equation by x
100=0.5*x       - we divide both sides of the equation by (0.5) to get x
100/0.5=x 
200=x 
x=200

now we have: 
120 is 200% of 60