Q. An urn contains 3 red and 5 blue balls. The probability that two balls are drawn in which 2nd ball drawn is blue without replacement, is
A) $\frac{5}{16}$
B) $\frac{5}{56}$
C) $\frac{5}{8}$
D) $\frac{20}{56}$
Explanation
(c)
Required probability
$= P(I$st is red and IInd is blue)
$= P$(Ist is blue and IInd is also blue)
$= \frac{3}{8} \times \frac{5}{7} + \frac{5}{8} \times \frac{4}{7} = \frac{5}{8}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.