SOLUTION: Jada has a total of 21 coins, only dimes and quarters. She has $3.15.how many of each coins does she have?

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Question 1026950: Jada has a total of 21 coins, only dimes and quarters. She has $3.15.how many of each coins does she have?

Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
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D=number of dimes; Q=number of quarters
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D+Q=21
D=21-Q . Use this to substitute for D below.
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$0.10(D)+$0.25(Q)=$3.15 . Substitute for D from above.
$0.10(21-Q)+$0.25(Q)=$3.15
$2.10-$0.10Q+$0.25Q=$3.15
$0.15Q=$1.05
Q=7
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ANSWER 1: She has 7 quarters.
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D=21-Q=21-7=14
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ANSWER 2: She has 14 dimes.
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CHECK:
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$0.10(D)+$0.25(Q)=$3.15
$0.10(14)+$0.25(7)=$3.15
$1.40+$1.75=$3.15
$3.15=$3.15
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