SOLUTION: A bag contains 30 coins, all of which are either quarters or dimes. If the total value of the coins is $5.85, how many of each kind are there?

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Question 1036386: A bag contains 30 coins, all of which are either quarters or dimes. If the total value of the coins is $5.85, how many of each kind are there?
Found 2 solutions by macston, ikleyn:
Answer by macston(5194)   (Show Source):
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Q=number of quarters; D=number of dimes
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Q+D=30
D=30-Q . Use this to substitute for D below
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$0.10D+$0.25Q=$5.85 . Substitute for D from above.
$0.10(30-Q)+$0.25Q=$5.85
$3.00-$0.10Q+$0.25Q=$5.85
$0.15Q=$2.85
Q=19
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ANSWER 1: There were 19 quarters.
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D=30-Q=30-19=11
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ANSWER 2: There were 11 dimes.
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CHECK:
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$0.10D+$0.25Q=$5.85
$0.10(11)+$0.25(19)=$5.85
$1.10+$4.75=$5.85
$5.85=$5.85
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Answer by ikleyn(52788)   (Show Source):
You can put this solution on YOUR website!
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For coin problems and their detailed solutions see the lessons in this site:
    - Coin problems
    - More Coin problems
    - Solving coin problems without using equations
    - Kevin and Randy Muise have a jar containing coins
    - Typical coin problems from the archive

Read them attentively and become an expert in this field.