Events A and B are independent, with P(A∣B)=31 and P(B)=21.
For independent events, P(A∣B)=P(A).
(Translation: If A and B don't affect each other, then the probability of A given B has happened is just the probability of A)
Since P(A∣B)=31, this means P(A)=31.
For independent events:
P(A∩B)=P(A)×P(B)
Substituting the values:
P(A∩B)=31×21
P(A∩B)=61
Alternatively, using the conditional probability formula:
P(A∣B)=P(B)P(A∩B)
Rearranging:
P(A∩B)=P(A∣B)×P(B)
P(A∩B)=31×21
P(A∩B)=61
Therefore, P(A∩B)=61.