Hi,
Let x and (35-x)represent the quarters and nickels respectively
Question states:
25x + 5(35-x) = 255 cents
20x = 255 - 5*35
20x = 80
x = 4, the number of quarters, number of nickels = 31 (35-4)
CHECKING our Answer
25*4 + 5*31 = 100 + 155 = 255 cents = $2.55