Q.
Let $B_n$ denotes the event that $n$ fair dice are rolled once with $P\left(B_n\right)=\frac{1}{2^n}, n \in N$.
e.g. $P\left(B_1\right)=\frac{1}{2}, P\left(B_2\right)=\frac{1}{2^2}, P\left(B_3\right)=\frac{1}{2^3}, \ldots \ldots \ldots$ and $P\left(B_n\right)=\frac{1}{2^n}$
Hence $B _1, B _2, B _3, \ldots \ldots \ldots B _{ n }$ are pairwise mutually exclusive and exhaustive events as $n \rightarrow \infty$. The event $A$ occurs with atleast one of the event $B_1, B_2, \ldots \ldots ., B_n$ and denotes that the sum of the numbers appearing on the dice is $S$.
Probability that greatest number on the dice is 4 if three dice are known to have been rolled, is
Probability - Part 2
Solution: