Question 180898: Joe has a collection of nickels and dimes that is worth $6.05. If the number of dimes was doubled and the number of nickels was decreased by 10, the value of the coins would be $9.85. How many dimes does he have?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Joe has a collection of nickels and dimes that is worth $6.05. If the number of dimes was doubled and the number of nickels was decreased by 10, the value of the coins would be $9.85. How many dimes does he have?
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Equations:
5n + 10d = 605 cents
5(n-10) + 10(2d) = 985 cents
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Rearrange:
n + 2d = 121
5n + 20d - 1035 = 0 ; n + 4d - 207 = 0
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Modify:
n + 2d = 121
n + 4d = 207
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Subtract 1st from 2nd to get:
2d = 86
d = 43 (number of dimes)
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Substitute to solve for n:
n+ 2*43 = 121
n = 35 (number of nickels)
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Cheers,
Stan H.
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cheers,
Stan H.
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