(a)
Probability of success, $P = \frac{2}{6} = \frac{1}{3}$ and probability of failure, $q = \frac{2}{3}$
$\therefore$ Required probability$= \ ^{5}C_{4}\left( \frac{1}{3} \right)^{4}\left( \frac{2}{3} \right)$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.