Question 343930
She has a total of 84 coins, and the total dollar value of all dimes and quarters is $15. 
Write two equations, using variables “d” and “q” to represent the number of dimes and quarters Susan has. 
Solve those two equations using either the substitution or elimination method to find how many dimes and how many quarters she has.
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Quantity Eq.:::: d + q = 84
Value Eq::::::: 10d+25q = 1500 cents
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Multiply thru the 1st by 10.
10d + 10q = 10*84
10d + 25q = 1500
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Subtract 1st from 2nd and solve for "q":
15q = 660
q = 44 (# of quarters)
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Since d+q = 84, d = 40 (# of dimes)
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Cheers,
Stan H.
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