A fair die is rolled three times. What is the probability that it comes up
3 at least once?
The sample space in a 3 times die roll is equal to
6*6*6=216
The probability of getting no 3 in a single roll is P=5/6
thus
probability of getting NO 3 in three die rolls is
P=(5/6)*(5/6)*(5/6)
P=125/216
P(getting at least one 3)=1-P(getting NO 3)
P(getting at least one 3)=1-125/216
P(getting at least one 3)=91/216