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Question

Amy’s piggy bank is filled with either nickels or dimes. If she has a total of $2.00 and has exactly 26 coins, how many nickels does she have?

Answer 1

Amy has N nickels and D dimes.

n + d = 26

5n + 10d = 200 in pennies

But d = 26-n, so

5n + 10(26-n) = 200

5n + 260 - 10n = 200

260 - 5n = 200

-5n = -60

n = 12

then d = 26-n = 26-12 = 14

14 dimes and 12 nickels is

$1.40 + 0.60 = $2.00

14 dimes and 12 nickles