Posted by C on .
The coffee counter charges $9.00 per pound for Kenyan French Roast coffee and $8.00 per pound for Sumatran coffee. How much of each type should be used to make a 20lb blend that sells for $8.40 per pound?
Answer: Kenyan8 lb; Sumatran12 lb.
Can someone help me with how they arrived at this answer? Thank you

algebra 
Reiny,
9x + 8(20x) = 8.4(20)
9x + 160  8x = 168
x = 8
20x = 208 = 12