SOLUTION: sally has only dimes and quarters in her pocket. she has 21 coins all together with a total value of $4.35. how many of each coin type does she have?

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Question 1093652: sally has only dimes and quarters in her pocket. she has 21 coins all together with a total value of $4.35. how many of each coin type does she have?
Found 2 solutions by addingup, josgarithmetic:
Answer by addingup(3677) About Me  (Show Source):
You can put this solution on YOUR website!
d + q = 21 subtract quarters from both sides:
d = 21 - q
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0.10d + 0.25q = 4.35 substitute for d:
0.10(21 - q) + 0.25q = 4.35
2.1 - 0.10q + 0.25q = 4.35
0.15q = 2.25
q = 2.25/0.15
q = 15 She has 15 quarters and
21-15 = 6 dimes
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Check
0.10(6) = 0.60
0.25(15) = 3.75
0.60 + 3.75 = 4.35 correct

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
system%28d%2Bq=21%2C10d%2B25q=435%29

Money Equation equivalent to 2d%2B5q=87

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2d%2B5q-2d-2q=87-42, will give the value for q...
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15 quarters
and
6 dimes