You don't need to find the right answers, you are finding approximations of the answers.
75/99 = 3/4
13/25 = 1/2
19/100 = 1/5
11/72 = 1/6
41/63 = 5/8
28/71 = 7/18
24/99 = 1/4
19/98 = 1/4
So essentially what I did was round to the nearest fractions that can be simplified, then made it as small as possible. 75/99 = 75/100 = 3/4