Question 337824
Susan paid for her library fine with 12 coins consisting of nickels and dimes. If the fine was $0.95, how many coins were nickels?
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The hard way:
n = nickels, d = dimes
n + d = 12
5n + 10d = 95 --> n + 2d = 19
n + 2d = 19
n + d = 12
------------ Subtract
d = 7
n = 5
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The easy way:
12 nickels = 60 cents
Each nickel replaced by a dime adds 5 cents
95-60 = 35
35/5 = 7
--> 7 dimes, 5 nickels