posted by Melanie .
The manager has one type of coffee that sells for $5 per pound and another type that sells for $11 per pound. The manager wishes to mix 90 pounds of the $11 coffee to get a mixture that will sell for $10 per pound. How many pounds of $5 coffee should be used?
let the number of pounds of the cheaper kind be x
solve for x
11(90) + 5x = 10(90+x)