Question 703523
Assume x lbs of $6/lb is coffee is mixed while (30 - x) lbs of $4.5/lb coffee is mixed.

(6x + 4.5(30 - x))/30 = 5.2

1.5x + 135 = 156

x = 21(2/3) = 14 lbs

30 - x = 16 lbs