Question 365568
A pound of cashews sells for $6 per pound and a pound of peanuts sells for $3 per pound. If you would like to make a 4 pound mixture of peanuts and cashews at a cost of $4 per pound, how many pounds of cashews must you use? 
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Let x = pounds of cashews
then because there is a total of 4 pounds we have
4-x = pounds of peanuts
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"cost of cashews" + "cost of peanuts" = "cost of mix"
6x + 3(4-x) = 4(4)
6x + 12-3x = 16
3x + 12 = 16
3x = 4
x = 4/3
x = 1 and 1/3 pounds (cashews)
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Peanuts:
4-x = 4-4/3 = 12/3 - 4/3 = 8/3 = 2 and 2/3 pounds