Question

Three coins are tossed together. Find the probability of getting at least one head and one tail.

 

Answer 1

When three coins are tossed once, the sample space is given by
S = {HHH, HHT, HTH, HTT, THH, THT, TTH, TTT}
i.e. n (S) = 8

Let E₃ = event of getting at least one head and one tail
Then E₃ = {HHT, HTH, HTT, THH, THT, TTH}
i.e. n(E₃) = 6

\[\therefore P\left( E_3 \right) = \frac{n\left( E_3 \right)}{n\left( S \right)} = \frac{6}{8} = \frac{3}{4}\]