- Answer: 39 lbs of coffee a. was used
Explanation:
We need to set up two expressions with two variables to answer this question. First let's set up the relationship that accounts for the unit cost of the coffees and the total cost for the blend.
5.65*A + 4.25*B = 717.6
Then we need an expression that compares the amount of each coffee used for the blend. Since three times of B was used, we can write the expression
3A = B
Take this and plug in 3A for B in the first expression so you get
5.65*A + 4.25*3A = 717.6
Work it through and simplify. You get 18.4*A = 717.6. Divide 18.4 into 717.6 to get 39 lb of coffee was used