Question

A fair coin is tossed twice in succession. The set of equally likely outcomes is {HH, HT, TH, TT}. What is the probability of getting exactly two tails?

Answer 1

Answer: 0.25

Explanation:

Given : A fair coin is tossed twice in succession.

The set of equally likely outcomes is {HH, HT, TH, TT}.

i.e. The total number of outcomes = 4

In order to get exactly two tails , the total number of favorable outcomes = 1 (TT)

We know that ,
`\text{Probability }=\frac{\text{Favorable outcomes}}{\text{Total number of outcomes}}`

Then, the probability of getting exactly two tails =
`(1)/(4)=0.25`

Hence, the required probability = 0.25

Answer 2

The probability is 1/4
This is because:
Probability of first tails = 1/2
Probability of second tails = 1/2
Probability of first AND second tails = 1/2 * 1/2
= 1/4
This is also visible in the set of outcomes