Question

You roll a number cube twice. What is the probability of rolling a 2 first and then rolling an odd number?

Answer 1

you have a 50% to 75% chance 

Answer 2

The probability is
`(1)/(12)`

Explanation:

Define the events
`A` and
`B` as the events "rolling a 2" and "rolling an odd number", respectively. Notice that the result of every rolling is independent of the previous results, so the event
`A\cap B` describes the phenomenon we are analazying.

On the other hand, we have that the probability of rolling a 2 is
`(1)/(6)` and the probability of rolling an odd number is
`(1)/(2)`, thus

`P(A\cap B) = P(A)\cdot P(B) = (1)/(6)\cdot (1)/(2) = (1)/(12)`.