Browse Questions

# If $\large\frac{2}{11}$ is the probability of an event,what is the probability of the event 'not A'

$\begin{array}{1 1}(A)\;\large\frac{9}{11}\\(B)\;\large\frac{8}{11}\\(C)\;\large\frac{5}{11}\\(D)\;\large\frac{6}{11}\end{array}$

Can you answer this question?

Toolbox:
• Sum of the event and its complementary event is always 1
• $\therefore P(A)+P(A')=1$
Let A be the event
Given $P(A)=\large\frac{2}{11}$
$\therefore$ P(not A)=P(A')=1-P(A)
$\Rightarrow 1-\large\frac{2}{11}$
$\Rightarrow\large\frac{9}{11}$
$\therefore P(A')=\large\frac{9}{11}$
Hence (A) is the correct answer.
answered Jul 1, 2014