How many pounds of coffee worth $7.50 per pound must be blended with coffee worth $9.50 per pound to make a mixture of 12 pounds of coffee worth $8.00 per pound?

Answer 1

the value of the coffee in each part must add up to the whole. So,

7.50x + 9.50(12-x) = 8.00(12)
x = 9

so,
9 lbs at $7.50 and
3 lbs at $9.50