Question 477653
Joe has a collection of nickels and dimes that is worth $5.65. If the number of dimes were doubled and the number of nickels were increased by 8, the value of the coins would be $10.45. How many dimes does he have? 
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Value Equation: 5n  +  10d = 565 cents
Value Equation: 5(n+8)+10(2d) = 1045 cents
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Modify:
5n + 10d = 565
5n + 20d = 1005
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Subtract and solve for "d":
10d = 440
d = 44 (# of dimes)
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Solve for "n":
5n + 10d = 565
5n + 440 = 565
5n = 125
n = 25 (# of nickels
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Cheers,
Stan H._