15/60 = 1/4 or 25 %
or
n% x 60 = 15 (the statement you wrote above changed into math)
.60n = 15 What allows me to move the decimal back two places? Normally you can change a percent to a decimal by moving it back two places. But if you don't know what the % is, you can move the number you are multiplying by back two places instead.
For example: 37 x .45 = .37 x 45 both = 16.65 - this shows that it doesn't matter which number is moved back two places - the answer will be the same. You can't move n% back two places (because you can't move a number you don't know back two places) so just move the number you are multiplying by, namely 60, back two place - that is how I got .60
.60n=15
.60 .60 divide both sides by .60
n= 25%