Question 1139186: If Dylan has 12 nickels and quarters in his pocket, and they have a combined value of 220 cents, how many of each coin does he have? Answer by greenestamps(13200) (Show Source):
there are 12 coins total the total value of the coins is 220 cents
Solve by whatever method you want....
Elimination looks easiest -- multiply the first equation by -5 and add the resulting equation to the second equation, eliminating n; then go from there.
Using logical reasoning and simple mental arithmetic...
(1) If all 12 coins were quarters, the total would be 12*25 = 300 cents; that is (300-220) = 80 cents more than the actual total.
(2) Exchanging one of the quarters for a nickel keeps the total number of coins at 12 and decreases the total value by (25-5) = 20 cents.
(3) You have to do that 80/20 = 4 times to get the total down to the correct 220 cents.
