SOLUTION
A coin was flipped.
A = probability of it landing on a head
B = probability of it landing on a tail.
We are asked P(A and B), that means probability of landing on a head and on a tail.
A coin can only land on a head or it can land on a tail. It can't land on a head and a tail at the same time.
Therefore the probability of landing on a head and a tail is 0.
Hence, the answer is 0.