Answer: The required number of cans is 7.
Step-by-step explanation: Given that 24 extra large cans of soup will serve 96 people.
We are to find the number of cans that Ann should buy to serve 28 people.
We will be using the UNITARY method to solve the given problem.
We have
Number of can of soup that will serve 96 people = 24.
So, the number of can of soup that will serve 1 people will be

Therefore, the number of cans of soup that will serve 28 people is given by

Thus, the required number of cans is 7.