SOLUTION: if i have 20 coins all dimes and quarters and total is $2.90 cent. How many of each coin do i have

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Question 216619: if i have 20 coins all dimes and quarters and total is $2.90 cent. How many of each coin do i have
Answer by RAY100(1637) About Me  (Show Source):
You can put this solution on YOUR website!
Let d = # dimes,,,,,,,,,and q= # quarters
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(1) d + q = 20,,,,or q=20-d
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(2) .1d +.25q = 2.90,,,,,,,,amt of money
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subst (1) into (2)
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.1d +.25(20-d) = 2.90
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.1d -.25d +5 = 2.90
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-.15 d = - 2.10
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d=14,,,,,,,,,and q=20-d = 6
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check,,,.1(14) + .25(6) = 1.40 + 1.50 = 2.90,,,,,ok
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