SOLUTION: Sara is a cashier at a grocery store. She has counted 76 bills with a total of $580 consisting of $5 and $10 bills. How many of each type does she have?

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Sara is a cashier at a grocery store. She has counted 76 bills with a total of $580 consisting of $5 and $10 bills. How many of each type does she have?      Log On


   

Question 974970: Sara is a cashier at a grocery store. She has counted 76 bills with a total of $580 consisting of $5 and $10 bills. How many of each type does she have?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = number of $5 bills
Let +b+ = number of $10 bills
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(1) +a+%2B+b+=+76+
(2) +5a+%2B+10b+=+580+
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Multiply both sides of (1) by +5+
and subtract (1) from (2)
(2) +5a+%2B+10b+=+580+
(1) +-5a+-+5b+=+-380+
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+5b+=+200+
+b+=+40+
and
(1) +a+%2B+40+=+76+
(1) +a+=+36+
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She has 36 $5 bills and
40 $10 bills
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check:
(2) +5a+%2B+10b+=+580+
(2) +5%2A36+%2B+10%2A40+=+580+
(2) +180+%2B+400+=+580+
(2) +580+=+580+
OK