Question

A bag contains 3 black, 3 white and 2 red balls. Three balls are drawn without replacement one-by-one. The probability that the third ball is red, is

• A. $ \theta ={{\sin }^{-1}}\left[ \frac{\lambda }{3d} \right] $
• B. $ V=\frac{Q}{C}=Q.\frac{d}{{{\varepsilon }_{0}}A} $
• C. $ \eta =1-\frac{{{T}_{2}}}{{{T}_{1}}}=1-\frac{500}{800} $
• D. $ =\frac{3}{8}=0.375 $

Answer 1

Answer: (D)

Three possible cases arise
$ IIst $ draw
$ IInd $ draw
$ III\text{ }rd $ draw
Red Non-red Non-red
Non-red Red Non-red
Red Red Red
$ \therefore $ Required probability $ =\frac{2}{8}\times \frac{6}{7}\times \frac{1}{6}+\frac{6}{8}\times \frac{2}{7}\times \frac{1}{6}+\frac{6}{8}\times \frac{5}{7}\times \frac{2}{6} $ $ =\frac{2}{56}+\frac{2}{56}+\frac{10}{56}=\frac{14}{56} $