Answer:
Explanation:
The number of ways the hospital can purchase 5 machines and receive at least 2 of the defective machines is calculated as follows:
The number of ways the hospital can receive exactly 2 defective machines is C(4,2) = 6, where C(n, k) is the number of combinations of n things taken k at a time.
The number of ways the hospital can receive exactly 3 defective machines is C(4,3) = 4.
The number of ways the hospital can receive exactly 4 defective machines is C(4,4) = 1.
So, the total number of ways the hospital can purchase 5 machines and receive at least 2 of the defective machines is 6 + 4 + 1 = 11.