Final answer:
Darryl should buy 17 bags of the 5 pound size. The total cost of the coffee would be 204.
Step-by-step explanation:
To determine which size bag Darryl should buy, we need to find the size that gives him a total of at least 84 pounds of coffee. Looking at the table, we can see that the 5 pound bag costs $12. This means Darryl would need to buy 84/5 = 16.8 bags to get 84 pounds of coffee. Since he cannot buy a fraction of a bag, he would need to round up to the nearest whole number, which is 17. Therefore, Darryl should buy 17 bags of the 5 pound size.
The total cost of the coffee can be found by multiplying the number of bags by the price per bag. In this case, the total cost would be 17 * 12 = 204.