Q. A person draws out two balls successively from a bag containing 6 red and 4 white balls. The probability that at least one of them will be red, is
A) $\frac{78}{90}$
B) $\frac{30}{90}$
C) $\frac{48}{90}$
D) $\frac{12}{90}$
Explanation
(a)
Required probability=$P(WR) + P(RW) + P(RR)$
$= \frac{6}{10} \times \frac{4}{9} + \frac{4}{10} \times \frac{6}{9} + \frac{6}{10} \times \frac{5}{9}$
$= \frac{24 + 24 + 30}{90} = \frac{78}{90}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.