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# Determine the probability P,for each of the following events.Atleast one head in two tosses of a fair coin.

$\begin{array}{1 1}(A)\;\large\frac{3}{4}\\(B)\;\large\frac{2}{5}\\(C)\;\large\frac{3}{7}\\(D)\;\large\frac{4}{5}\end{array}$

Can you answer this question?

Step 1:
Atleast one head in two tosses of a fair coin.
$\therefore$ Sample space of two tosses of a fair coin =$\{HH,HT,TH,TT\}$
Atleast one head $n(E)=\{HH,HT,TH\}$
Step 2:
$\therefore$ Probability =$\large\frac{n(E)}{n(S)}$
$\Rightarrow \large\frac{3}{4}$
Hence (A) is the correct answer.
answered Jul 8, 2014