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Home  >>  CBSE XII  >>  Math  >>  Probability
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A flash light has 8 batteries out of which 3 are dead.If two batteries are selected without replacement and tested,the probability that both are dead is

$\begin{array}{1 1}(A)\;\frac{33}{56}\quad(B)\;\frac{9}{64}\quad(C)\;\frac{1}{14}\quad(D)\;\frac{3}{28}\end{array} $

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1 Answer

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Toolbox:
  • oubasict of 8 batteries 3 are dead
  • 2 batteries are selected
  • without replacement
  • p(getting a dead battery)=\(\Large\frac{3}{8}\)
  • p(getting second also dead)=\(\Large\frac{2}{7}\)
p(both dead)=\(\Large\frac{3}{8}\)X\(\Large\frac{2}{7}\)
=\(\Large\frac{3}{28}\)
'D'option is correct

 

answered Feb 20, 2013 by poojasapani_1
edited Mar 15, 2013 by poojasapani_1
 

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