Given:
Type A
- cost: $5.35 per pound
Type B
-cost: $4.10 per pound
Uses twice as many pounds of type B as type A: B = 2A
Total cost - $487.80
Find: the number of pounds of Type A coffee used
Solution:
Let a = number of pounds used for Type A coffee
Let b = number of pounds used for Type B coffee
We know that the total cost for both coffee is $487.80 so, we can write equation 1:

We also know that this month's blend used twice as many pounds of type B coffee as type A. This means b = 2a. So, we can replace "b" in equation 1 with "2a". So, the equation 1 becomes:


To solve for a, first, add similar terms 5.35a and 8.2a.

Then, divide both sides of the equation by 13.55.


Therefore, 36 pounds of Type A coffee were used during this month.