How many pounds of Tanzanian and Kenya blend

Question

A coffee distributor needs to mix a Tanzanian coffee blend that normally sells for $8.80 per pound with a Kenya coffee blend that normally sells $10.50 per pound to create 80 pounds of a coffee that can sell for $9.37 per pound. How many pounds of each coffee should they mix?

Answer 1

If t and k represents the pounds of Tanzanian and Kenyan coffee, respectively, then:

t + k = 80

8.8t + 10.5k = 9.37(t+k)

Use the first equation to get one unknown in terms of the other and use that to substitute in the second equation.