15% written as decimal is 0.15, multiply this by the number to get 15% of that number.
0.15x = 18
x = 18/0.15
x = 120
Now the percent is the unknown number. We'll use p for percent.
110p = 88
p = 88/110
p = 0.8
written as a percent (multiply by 100) = 80%
