Java Joe Coffee Merchants makes 30 pounds of a blend that costs $4.80 per pound. This blend is made by mixing a Costa Rican coffee that costs $6 per pound with a Colombian coffee that costs $4 per pound. How many pounds of each coffee do they use in the blend?

they used 12 pounds of Costa Rican coffee and 18 pounds of Colombian coffee

Step-by-step 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