A fair dice is rolled . the probability that the first time one occur at even no. of trails
Can any one explain me using Tree Diagram.
You may throw a one straight away, or on throw 2, or on throw 3, or on throw 4, or ...........
P(one at first throw) = 1/6
P(one at second throw) = 5/6 times 1/6 = 5/36
P(one at third throw) = 5/6 x 5/6 x 1/6 = 25/216
As this goes on for ever you need to know how to do the sum to infinity of a geometric progression. Post again if you want help with that.
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