I need help with my algebra word problem homework!

Question

How many pounds of coffee worth $5 per pound must be mixed with 20 pounds of Brazilian coffee worth $4 per pound to produce a mixture worth $4.20 per pound?

Answer 1

Let x be the amount of $5 coffee you need to add to the 20 lbs of Brazilian coffee.

 

(20 lbs)($4 per lbs) + (x lbs)($5 per lbs) = (20+x)($4.20)

80 + 5x = 84 + 4.2 x

 

Solve for x.