Five dice are thrown simultaneously.If the occurrence of an even number in a single dice is considered a success, then the probability of at most 3 successes is |
$\frac{15}{16}$ $\frac{13}{16}$ $\frac{11}{16}$ $\frac{1}{16}$ |
$\frac{13}{16}$ |
The correct answer is Option (2) → $\frac{13}{16}$ ** Success probability on one die = $\frac{1}{2}$ Number of trials = $5$ $P(X\le 3)=\sum_{k=0}^{3}\frac{5!}{k!(5-k)!}\left(\frac{1}{2}\right)^5$ Compute terms: For $k=0$: $\frac{5!}{0!5!}\left(\frac{1}{2}\right)^5 = 1\cdot\frac{1}{32}=\frac{1}{32}$ For $k=1$: $\frac{5!}{1!4!}\left(\frac{1}{2}\right)^5 = 5\cdot\frac{1}{32}=\frac{5}{32}$ For $k=2$: $\frac{5!}{2!3!}\left(\frac{1}{2}\right)^5 = 10\cdot\frac{1}{32}=\frac{10}{32}$ For $k=3$: $\frac{5!}{3!2!}\left(\frac{1}{2}\right)^5 = 10\cdot\frac{1}{32}=\frac{10}{32}$ Total $=\frac{1+5+10+10}{32}=\frac{26}{32}=\frac{13}{16}$ The probability of at most 3 successes is $\frac{13}{16}$. |