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. Find the probability that the event A happens atleast once.

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

Answer 1

The correct option is B $0.784$

As the probability that event happens is 0.4.

So the probability that event will not happen $=1-0.4=0.6$

And the events are mutually independent of each other. So probability of each event will not be affected. If in all the three trials, event will not happen, the probability will be = $0.6\times 0.6\times 0.6=0.216$

So the probability that event will happen at least once $=1-$ (Probability of event that will not happen)

So, P(at least once) =$1-0.216=0.784$