You roll two dice. What is the probability of getting a 3 or a 6 on the second die, given that you rolled a 1 on the first die?

1 Answer
EZ as pi
Apr 9, 2018

# P(3 or 6) =1/3#

Explanation:

Notice that the outcome of the first die does not affect the outcome of the second. We are only asked about the probability of a #3or 6# on the second die.

There are #63# numbers on a die, of which we want two - either #3 or 6#

#P(3 or 6) = 2/6 = 1/3#

If you are wanting the probability for both dice, then we have to consider the probability of getting the #1# first.

#P(1,3) or (1,6) = P(1,3) +P(1,6)#

#= (1/6 xx 1/6) + (1/6 xx 1/6)#

#=1/36 +1/36 = 2/36 = 1/18#

We could also have done: #1/6 xx 1/3 = 1/18#

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