Marginalization of joint distribution
Guide:

To solve the problem, we have to assume that there is the outcome of the dice and the outcome of the coins are independent. 

We let $C$ denotes the event that the coin lands on tail and $D$ be the event that the dice outcome is $1$.

You have been given that the coin lands on tails or  the dice lands on $1$, and you are interested in finding out that the coin lands on tails and  the dice lands on $1$.

You want to compute $P(W|Q)=\frac{P(W\cap Q)}{P(Q)}=\frac{P(W)}{P(Q)}=\frac{P(C)P(D)}{P(Q)}$.

To compute $P(Q)$ where $Q= C \cup D$. You can either use $$P(Q)= P(C)+P(D)-P(C\cap D)$$

or $$P(Q)=1-P(Q^c)=1-P(C^c \cap D^c)$$

Given all these formulas, hopefully you can solve for $P(W|Q)$.