Question

If 28% of a sum is $100.80, what is the sum?

Answer 1

28.22
Take .28 and multiply it by 100.8 to find the sum

Answer 2

You can cross multiply to find this. Put the amount you're trying to find (x) over 100.80, and set it equal to 28/100.
x/100.8 = 28/100
100.8 x 28 = 100x
2822.4 = 100x
/100
28.224 = x