SOLUTION: A backpacker wishes to mix peanuts worth $2 per pound and trail mix worth $5 per pound to make 10 pounds of a cheaper trail mix to take on the family backpacking trip to the Sierra

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: A backpacker wishes to mix peanuts worth $2 per pound and trail mix worth $5 per pound to make 10 pounds of a cheaper trail mix to take on the family backpacking trip to the Sierra      Log On


   



Question 910903: A backpacker wishes to mix peanuts worth $2 per pound and trail mix worth $5 per pound to make 10 pounds of a cheaper trail mix to take on the family backpacking trip to the Sierra mountains. If the back packer could find the blend in the grocery store it would sell for $3.20 per pound. How many pounds of each should be in the mixture if it's worth $3.20 per pound?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = pounds of peanuts needed
Let +b+ = pounds of trail mix needed
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(1) +a+%2B+b+=+10+
(2) +%28+2a+%2B+5b+%29+%2F+10+=+3.2+
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(2) +2a+%2B+5b+=+32+
Multiply both sides of (1) by +2+ and
subtract (1) from (2)
(2) +2a+%2B+5b+=+32+
(1) +-2a+-+2b+=+-20+
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+3b+=+12+
+b+=+4+
and, since
(1) +a+%2B+b+=+10+
(1) +a+%2B+4+=+10+
(1) +a+=+6+
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6 pounds of peanuts and
4 pounds of trail mix are needed
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check:
(2) +%28+2%2A6+%2B+5%2A4+%29+%2F+10+=+3.2+
(2) +%28+12+%2B+20+%29+%2F+10+=+3.2+
(2) +32+=+32+
OK