A room contains 3 brown, 5 black and 4 white chairs. Two chairs are picked and a

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Home Aptitude

Question
A room contains 3 brown, 5 black and 4 white chairs. Two chairs are picked and are put in the lawn. What is the probability that none of the chairs picked is white ?
Options
A. 14/33
B. 14/55
C. 12/55
D. 13/33

Correct Answer

14/33

Explanation

Total number of chairs = (3 + 5 + 4) = 12.

Let S be the sample space.

Then, n(s)= Number of ways of picking 2 chairs out of 12

$=^{12} 12_{2} = \frac{12 \times 11}{2 \times 1} = 66$

Let n(E) = number of events of selecting 2 chairs for selecting no white chairs.

$=^{8} C_{2} = \frac{8 \times 7}{2 \times 1} = 28$

Therefore required probability = 28/66 = 14/33.

Tags:

CAT