Question

a fair coin is tossed 2 times in succession. the set of equally likely outcomes is . find the probability of getting at least one tail.

Answer 1

Answer: 3/4

Why:

The only way in which at least one tail will not occur is if both tosses give heads.

S=HH,HT,TH,TT

The probability of this is the probability of a single head multiplied by itself.


The probability of this is approximately 1/2, so the probability of two in a row is:

1/2 x 1/2 = 1/4
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If the probability of getting no tails is 1/4, the probability of getting at least one tail is:

1 - 1/4 = 3/4
​