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# A coin is tossed thrice. The probability of getting head at least once is

$\begin {array} {1 1} (1)\;\large\frac{3}{8} & \quad (2)\;\large\frac{1}{8} \\ (3)\;\large\frac{1}{4} & \quad (4)\;\large\frac{7}{8} \end {array}$

We have P( at least one head ) = 1-P ( no head)
$= 1-P(TTT)$
$=1- \large\frac{1}{2} \times \large\frac{1}{2} \times \large\frac{1}{2}$
$1 - \large\frac{1}{8}$
$= \large\frac{7}{8}$
Ans : (D)
edited Aug 11, 2014