SOLUTION: A collection of 75 dimes and quarters is worth $13.65. How many of each coim are there? Solbe by using weighted averages.

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Question 810645: A collection of 75 dimes and quarters is worth $13.65. How many of each coim are there? Solbe by using weighted averages.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A collection of 75 dimes and quarters is worth $13.65. How many of each coim are there?
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Quantity Eq:: d + q = 75 coins
Value Eq::: 10d+25a = 1365 cents
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Modify for elimination::
10d + 10q = 10*75
10d + 25q = 1365
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Subtract and solve for "q":
15q = 615
q = 41 (# of quarters)
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Solve for "d":
d + q = 75
d + 41 = 75
d = 34 (# of dimes)
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Cheers,
Stan H.
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