2x-y=23 & x-9=-1 by substitution

If the scale factor between two circles is 2x/5y what is the ratio of their areas?

When solving this problem: 3025/5.5 = a/90.75 you get 49912.5 which would be the length of one of the sides of a square when the area is only 90.75 inches. is that answer correct, why, and how is it possible?

Apackage of five erasers cost 0. $.39 at this rate how many how much would 60 erasers cost in dollars and cents