For two events A and B with $P(A) =\frac{1}{2}$, $P(B) =\frac{1}{3}$, $P(A∩B) =\frac{1}{4}$ and P(A' ∩ B') is equal to:

$\frac{7}{12}$ $\frac{5}{6}$ $\frac{5}{12}$ $\frac{3}{4}$

$\frac{5}{6}$

In the given problem we have PA) = 1/2, P(B) = 1/3, P(A∩B) = 1/4 We know that P (A′∩B′) = 1- P(A) - P(B) -P(A∩B)                                    = 1- (1/2)-(1/3) + 1/4       So, P (A′∩B′)           = 5/6