SOLUTION: 10.60 in a jar of 100 coins quarters & dimes. How many dime in the jar? Please show how to set up.

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Question 597010: 10.60 in a jar of 100 coins quarters & dimes. How many dime in the jar? Please show how to set up.
Answer by math-vortex(648) About Me  (Show Source):
You can put this solution on YOUR website!
Hi, there--
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Let q be the number of quarters in the jar.
Let d be the number of dimes in the jar.
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The amount of money in quarters is $0.25 times the number of quarters in the jar, so the value of all the quarters is
0.25q
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The amount of money in dimes is $0.10 times the number of dimes, so the value of the dimes is
0.10d
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There are 100 coins all together so
q%2Bd=100
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The total dollar amount in the jar is $10.60 so
0.25q%2B0.10d=10.60
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Now we have a system of two equations that we can solve. Rewrite the first equation in terms of d.
q%2Bd=100
d=100-q
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Substitute 100-q for d in the second equation.
0.25q%2B0.10%28100-q%29=10.60
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Simplify.
0.25q%2B0.10%28100-q%29=10.60
0.25q%2B%280.10%29%28100%29-0.10q=10.60
0.15q%2B10.00=10.60
0.15q=10.60-10.00
0.15q=0.60
q=4
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There are 4 quarters.
There are 100-4=96 dimes.
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CHECK your work.
Do 4 quar$9.60. A dollar plus $9.60 is $10.60...Check!!!
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That's it. Feel free to email me via gmail, if the explanation is unclear.
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Ms.Figgy
math.in.the.vortex@gmail.com