A coin is tossed twice, what is the probability that atleast one tail occurs ?
A coin is tossed twice, what is the probability that atleast one tail occurs ?
When a coin is tossed twice, the sample space is given by
$S =\{ HH , HT , TH , TT \}$
Let $A$ be the event of the occurrence of the least one tail.
Accordingly, $A=\{H T, T H, T T\}$
$\therefore P ( A )=\frac{\text { Number of outcomes favourable to } A }{\text { Total number of possibe outcomes }}$
$=\frac{n(A)}{n(S)}$
$=\frac{3}{4}$
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