SOLUTION: A child's bank contains $6.30 in dimes and quarters. There are twice as many dimes as quarters. How many of each kind of coin are there in the bank?

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Question 170521This question is from textbook Alegebra Sturucture and Method
: A child's bank contains $6.30 in dimes and quarters. There are twice as many dimes as quarters. How many of each kind of coin are there in the bank? This question is from textbook Alegebra Sturucture and Method

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A child's bank contains $6.30 in dimes and quarters. There are twice as many dimes as quarters. How many of each kind of coin are there in the bank?
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d = 2q
10d + 25q = 630
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Rearrange:
d - 2q = 0
10d + 25q = 630
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Use substitution to solve for "q":
10(2q) + 25q = 630
45q = 630
q = 14 (# of quarters)
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d = 2q = 28 (# of dimes)
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Cheers,
Stan H.