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

Question

A. $129.02
B. $277.78

C. $282.24

D. $360.00
how can i do this

Answer 1

Change 28% to a decimal. Let x = the sum.

0.28x = 100.8
x = 100.8/0.28
x = ?

Answer 2

i got the answer it's D thanks
how did you figure out which operation to use.

Answer 3

I thought -- 28% of what is 100.80? -- and then put it in algebraic terms.