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? 
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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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