Answer: 1/2
Because:
P(tail) = Probability of getting a tail on the coin
P(tail)=1/2
P(4)=Probability of getting the number '4' on the dice.
P(4)=1/6
P(tail and 4)=Probability of getting tail on the coin and number '4' on the dice.
P(tail and 4)=p(tail multiply with 4)
P(tail and 4)= 1/2×1/6
P(trail and 4)=1/12
Hope this helps!