Question 554389
Quarters = q
Dimes = 18-q

Total Value in cents = 25*q + 10*(18-q)
Total Value in cents = 25q+180-10q
Total Value in cents = 15q+180
Total Value in cents = 15(q+12)
Total value in Dollars = 15(q+12)/100
Total value in Dollars = 3(q+12)/20