Answer:

•8.74 pounds of robust blend

• 1.25 pounds of mild blend

Explanation:

We are given:

•12 ounces, 6 ounces of mild blend Colombian beans

•4 ounces, 10 ounces of mild blend Brazilian beans.

From the question, we get the following equations:

1) Colombian: 12x + 6y = 1800

2) Brazilian: 4x + 10y = 760

Let's multiply the Brazilian equation by 3, we now have:

Colombian: 12x + 6y = 1800

Brazilian : 12x + 30y = 2280

Solving simultaneously, we have:

-24y = - 480

Therefore,

y = -480/-24

y= 20 oz

y = 20 oz ( divide by 16 to convert to pounds) = 1.25 pounds

Let's solve for x from Brazilian equation:

4x + 10y = 760

Therefore, since y = 20, we have:

4x + 10(20) = 760

= 4x + 200 = 760

= 4x = 760 - 200

= 4x = 560

Therefore

x = 560/4

x = 140

140 oz = 8.74 pounds

Therefore, they should make;

8.74 pounds of robust blend and 1.25 pounds of mild blend.