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Two fair coins are tossed. What is the probability that at least one head occurs.

$\begin {array} {1 1} (1)\;\large\frac{2}{5} & \quad (2)\;\large\frac{3}{4} \\ (3)\;5 & \quad (4)\;\large\frac{1}{4} \end {array}$


1 Answer

Sample space 'S' of this experiment is
$S = { HH,\: HT,\: TH, \: TT}$
As the coins are fair all these outcomes are equally likely.
If 'A' is the event representing the event of at least one head
occuring then,
$A={ HT,\: TH, \: HH}$
$ \therefore P(A) = \large\frac{3}{4}$
Ans : (B)
answered Jan 2, 2014 by thanvigandhi_1
edited Aug 11, 2014 by sharmaaparna1