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.

Answer 1

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.