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Question
A game consists of tossing a one-rupee coin three times, and noting its outcome each time. Find the probability of getting at least two tails.
Solution
When a coin is tossed three times, all possible outcomes are
HHH, HHT, HTH, THH, HTT, THT, TTH and TTT.
Number of total outcomes = 8.
Outcomes with atleast two tails are TTH, THT, HTT and TTT.
Number of outcomes with atleast two tails = 4.
∴ P(getting at least two tails) = `("Number of favourable outcomes")/"Number of all possible outcomes"`
`= 4/8 = 1/2`
Thus, the probability of getting at least two tails is 1/2.
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