Answer:
27 lbs premium coffee and 45 pounds cheap brand
Explanation:
set up a system of equations
12.5P+4.5C = $15
p+c = 12
(solve this by elimination or substitution)
you get p = 3/4 and C = 5/4
This means it must be in a ration of 3 to 5.
3+5 = 8
and total 72 lbs/8 lbs = 9
3 x 9 = 27 and 5 x 9 = 45