SOLUTION: if you have $7/lb coffee and $2/lb coffee equaling 30 lbs how much of the $7 coffee do i add to make it $5/lb coffee?

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Question 430068: if you have $7/lb coffee and $2/lb coffee equaling 30 lbs how much of the $7 coffee do i add to make it $5/lb coffee?
Answer by jorel1380(3719) About Me  (Show Source):
You can put this solution on YOUR website!
If you have 30lbs of $5 coffee, then your total price should be 30X5, or $150 worth of coffee. This gives us two equations:
X + Y =30
7X + 2Y= 150
Multiply the first equation by 2, we get
2X+2Y=60
Subtract this equation from the 2nd equation, we get
5X=90
X=18
Therefore we need 18 lbs. of $7 coffee and (30-18)or 12 lbs. of $2 coffee.