Final answer:
To find out how many pounds of type A coffee Lisa used, we set up a system of equations based on weight and cost, and by solving, we determined that Lisa used 89 pounds of type A coffee.
Step-by-step explanation:
The student's question is related to creating a blend of two types of coffee and determining the quantity of each type needed for the blend given the costs and total weight. Let's denote the pounds of type A coffee as A and the pounds of type B coffee as B. From the information given, we know the following:
- The cost of type A coffee per pound is $5.80.
- The cost of type B coffee per pound is $4.45.
- The total weight of the blend is 145 pounds.
- The total cost of the blend is $765.40.
We can set up a system of two equations to find the values of A and B.
Weight equation: A + B = 145 pounds
Cost equation: 5.80A + 4.45B = $765.40
Now, we can solve for A using substitution or elimination. For example, using substitution, we can express B as (145 - A) from the weight equation and substitute it into the cost equation:
5.80A + 4.45(145 - A) = $765.40
Simplifying this, we have:
5.80A + 645.25 - 4.45A = $765.40
1.35A = $765.40 - 645.25
1.35A = $120.15
A = $120.15 / 1.35
A = 89 pounds
So, Lisa used 89 pounds of type A coffee in the blend.