Question 465846
My piggy bank contains $19.75 in dimes and quarters, there are 100 coins in all, how many dimes are there? 
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Quantity Eq: d + q = 100
Value Eq:: 10d+25q = 1975 cents
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Multiply thru 1st by 25
25d + 25q = 25*100
10d + 25q = 1975
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Substract and solve for "d":
15d = 525
d = 35 (# of dimes)
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Cheers,
Stan H.
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