Answer: 15 pounds of potatoes.
Explanation:
Kevin will perform basic multiplication to find how many potatoes he needs for all of the guests. Since each person requires 2 1/2 pound of potatoes and there are a total of 6 guests, multiplying these two values will find the pounds of potatoes that are needed for all of the guests.
2 1/2 * 6 = 15 pounds of potatoes
Therefore, Kevin needs 15 pounds of potatoes to make potato casserole for everyone at the dinner party.