Question

using a fair coin and a fair six-sided number cube, what is the probability of tossing tails and rolling a multiple of 3?

Answer 1

The multiple of 3 in a fair dice is 3 and 6, thus the probability of obtaining a multiple of 3 will be:
P(3 or 6)=1/6+1/6=1/3

Given a fair coin:
P(Tails)=1/2
thus
probability of tossing tails and rolling a multiple of 3
=1/2×1/3=1/6

Answer 2

$|\Omega|=2\cdot6=12\\ |A|=1\cdot2=2\\\\ P(A)=\dfrac{2}{12}=\dfrac{1}{6}\approx17%$