SOLUTION: A postal clerk sold 75 stamps for a total of $10.85. Some of the stamps were 15-cent stamps and the remainder of the stamps were 13 cent stamps. How many of the stamps were 13 ce

Question 207497: A postal clerk sold 75 stamps for a total of $10.85. Some of the stamps were 15-cent stamps and the remainder of the stamps were 13 cent stamps. How many of the stamps were 13 cent stamps?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A postal clerk sold 75 stamps for a total of $10.85. Some of the stamps were 15-cent stamps and the remainder of the stamps were 13 cent stamps. How many of the stamps were 13 cent stamps?
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Quantity Equation: f + t = 75
Value Equation:::15f+13t = 1085 cents
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Multiply thru the Quantity Equation by 15 to get:
15f + 15t = 15*75
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Subtract that from the Value Equation to get:
-2t = 1085-15*75
-2t = -40
t = 20 (# of thirteen cent stamps)
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Cheers,
Stan H.
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