Q.A fair die is tossed twice. What are the odds in favour of getting 4, 5 or 6 on the first toss and 1, 2, 3 or 4 on the second die? A) 1 : 3 B) 3 : 1 C) 1 : 2 D) 2 : 1

Odds express the same information as probability but as a ratio of favourable to unfavourable outcomes rather than a fraction of the total. If $m$ of $n$ equally likely outcomes favour event $A$, the odds in favour of $A$ are $m:(n-m)$, equivalently $P(A):P(A')$; the odds against $A$ are the reverse ratio $(n-m):m$, equivalently $P(A'):P(A)$. Given odds in one form, the corresponding probability is recovered as (favourable count)/(favourable + unfavourable count); conversely, given a probability, the odds …