SOLUTION: Bruce has 21 coins, all nickels and dimes, having a total value of $1.65. How many of each kind does he have? I'm having trouble with this so this is what I did so far: I took

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Question 646183: Bruce has 21 coins, all nickels and dimes, having a total value of $1.65. How many of each kind does he have?
I'm having trouble with this so this is what I did so far:
I took 1.65 and divided it by 21 and I got a total of 1.60 which meant he had 16 dimes and 1 nickel but to me it didn't make sense. Please tell me what I did wrong and how to solve the problem.

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Bruce has 21 coins, all nickels and dimes, having a total value of $1.65. How many of each kind does he have?
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Equations:
Quantity of coins: n + d = 21
Value of coins: 5n+10d = 165 cents
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Modify the 1st equation:
5n + 5d = 5*21
5n +10d = 165
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Subtract and solve for "d":
5d = 60
d = 12 (# of dimes)
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Solve for "n":
n + d = 21
n + 12 = 21
n = 9 (# of nickels)
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Cheers,
Stan H.
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