Question 597010
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+d=100}}}
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The total dollar amount in the jar is $10.60 so
{{{0.25q+0.10d=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+d=100}}}
{{{d=100-q}}}
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Substitute 100-q for d in the second equation.
{{{0.25q+0.10(100-q)=10.60}}}
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Simplify.
{{{0.25q+0.10(100-q)=10.60}}}
{{{0.25q+(0.10)(100)-0.10q=10.60}}}
{{{0.15q+10.00=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