Question 37431
Let x = number of pounds of $9 coffee.
The 100 - x = number of pounds of $12 coffee.
Then we write the "cost" equation:
9x + 12(100 - x) = (11.25)(100)
9x + 1200 - 12x = 1125
-3x = -75
x = 25
Thus 25 lbs of $9 and 75 lbs of $12 coffee.