Step-by-step explanation:
The die is rigged, so "not 3" is not a possibility. Ruling out those branches of the tree, there are 4 possible outcomes, one of which is the desired outcome. So the probability is 1/4.
A fair die has six sides that are equally likely, so the probability of rolling more than 2 is always 4/6. The outcome of the first roll does not effect the outcome of the second roll.
(Notice that we always have and
, then solve for
:
(this is the inverse)
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This inverse is valid only for . Why?
Suppose we take . Then
This would suggest that in the original equation, we should get when
. But when we check this, we end up with
which is clearly not true.