Answer:
they used 12 pounds of Costa Rican coffee and 18 pounds of Colombian coffee
Explanation:
Let x is the number of pounds of Costa Rican coffee
Let y is the number of pounds of Colombian coffee
Given that:
- Java Joe Coffee Merchants makes 30 pounds of a blend
<=> x + y = 30
<=> x = 30-y (1)
- A blend that costs $4.80 per pound => the total cost is: $4.8*30 = $144
<=> 6x + 4y = 144 (2)
We will substitute (1) into (2), we have:
6(30-y) + 4y = 144
<=> 180 - 6y + 4y = 144
<=> y = 2y = 36
<=> y =18 pounds
=> x = 30-18 = 12 pounds
So they used 12 pounds of Costa Rican coffee and 18 pounds of Colombian coffee