A collection of nickels, dimes and pennies has an average value of 7 cents per coin. If a nickel were replaced by five pennies, the average would drop to 6 cents per coin. What is the number of dimes in the collection?
+37146 Try 12 dimes 9 nickles 3 pennies = 168 168/24 = 7
12 dimes 8 nickles 8 pennies = 168 168/28 = 6
