You will need 2.3 pounds of corned beef and 2 pounds of cabbage for 40 people, Corned beef:1 pound of corned beef will serve 5 people. So, 40 people will need 40 / 5 = 8 pounds of corned beef. Cabbage:1 pound of cabbage will serve 4 people. So, 40 people will need 40 / 4 = 10 pounds of cabbage.