How many pounds of Brazilian coffee worth five dollars per pound must be mixed with 20 pounds of Columbian coffee was four dollars per pound to produce and make sure worth $4.20 per pound

Question

I need help with this problem! I can't figure out how to set it up?

Answer 1

Let B= pounds of Brazilian coffee.

Amount of mixture=B+20. Cost is 5B+4×20=4.2(B+20).

5B+80=4.2B+84.

0.8B=4, so B=4/0.8=40/8=5lb.