Question

A coin is tossed twice and the four possible outcomes are assumed to be equally likely. If A is the event, 'both head and tail have appeared' and B the event,' at most one tail is observed,' then the value of P(B/A) is ______.

Options

• 1

• 2

• `1/2`

• `1/4`

Answer 1

A coin is tossed twice and the four possible outcomes are assumed to be equally likely. If A is the event, 'both head and tail have appeared' and B the event,' at most one tail is observed,' then the value of P(B/A) is 1.

Explanation:

P(A) = `2/4` = `1/2`

P(B) = `3/4`

`P(B/A) = (P(B ∩ A))/(P(A)) = (1/2)/(1/2)` = 1