Question

The probability that an event $A$ happens in one trial of an experiment is $0.4$.Three independent trials of the experiment are formed. The probability that the event $A$ happens at least once is

• A. $0.936$
• B. $0.784,$
• C. $0.904$
• D. None of these

Answer 1

Answer: (B)

$0.784,$

Here $P\left(A\right)=0.4$ and $P\left(\overline{A}\right)=1-0.4=0.6$
probability that the event $A$ happens at least once $=1-P$ (event a does not happen in all three trials) $=1-0.6\times 0.6\times 0.6=0.784$