Question

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

• A. $0.934$
• B. $0.784$
• C. $0.548$
• D. $0.343$

Answer 1

The correct option is B $0.784$

Probability of occurrence of $A=0.4$
Probability of non-occurrence of $A=1-0.4=0.6$
Probability event $A$ happens at least once in three trials $=1-$ probability that event $A$ does not happen even once
$=1-(0.6{)}^3$
$=1-0.216$
$=0.784$

Hence, option B.