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Coin Problems. Example 1. A collection of nickels and dimes is worth $3.95. There are 8 more dimes than nickels. How many dimes and how many nickels are there?. Let n be the number of nickels. Let d be the number of dimes. 0.05n + 0.10d = 3.95. d = 8 + n. d = 8 + n.
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Example 1 A collection of nickels and dimes is worth $3.95. There are 8 more dimes than nickels. How many dimes and how many nickels are there? Let n be the number of nickels. Let d be the number of dimes. 0.05n + 0.10d = 3.95 d = 8 + n d = 8 + n 0.05n + 0.10(8 + n) = 3.95 d = 8 + 21 0.05n + 0.80 + 0.10n = 3.95 d = 29 5n + 80 + 10n = 395 21 nickels 80 + 15n = 395 29 dimes 15n = 315 n = 21
Example 2 Rob has $2.85 in nickels and dimes. He has twelve more nickels than dimes. How many of each coin does he have?
Example 3 Sally has 20 coins in her piggy bank, all dimes and quarters. The total amount of money is $3.05. How many of each coin does she have?