52-24=28 books were nonfiction
You must get the ratio if nonfiction to fiction
28/24= 7/6
I think your question is asking how much money he owes. He owes $90
70 = 50 * x/100
x = 70/50*100 = 140
Seventh is 140% of 50.
No one can tell you the answer to this. You need to provide us with a equation which we can solve.
