Answer :
assuming each guest isn't a fatty and every guest eats only 1 portion
320 times 8oz=2560 oz needed
number of cans needed times oz per can=oz we need
n times 40=2560
divide both sides by 40
n=64
64 cans needed
320 times 8oz=2560 oz needed
number of cans needed times oz per can=oz we need
n times 40=2560
divide both sides by 40
n=64
64 cans needed