Question 371292
Problem: Joe has $1.15 in dimes and nickles. The number of nickels is one less than twice the number of dimes. How many nickles and how many dimes does he have? 

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Method using two variable:
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Quantity Equation: n = 2d-1
Value Equation::: 5n + 10d = 115 cents
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Substitute for "n" and solve for "d":
5(2d-1) + 10d = 115
10d-5 + 10d = 115
20d = 120
d = 6 (# of dimes)
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Since n = 2d-1, n = 2*6-1 = 11 (# of nickels)
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Cheers,
Stan H.
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