Question

The probability of happening an event $A$ in one trial is $0.4$. The probability that the event $A$ happens atleast once in three independent trials is

• A. $0.936$
• B. $0.784$
• C. $0.904$
• D. $0.216$

Answer 1

Answer: (B)

$0.784$

Given, $P\left(A\right)=0.4$, then

$P\left(\overline{A}\right)=1-0.4=0.6$

Probability that $A$ does not happen at all $={\left(0.6\right)}^3$

Thus required probability is $1-{\left(0.6\right)}^3=0.784$.