Probability Question 76
Question: In a box there are 2 red, 3 black and 4 white balls. Out of these three balls are drawn together. The probability of these being of same colour is
[MP PET 1996]
Options:
A) $ \frac{1}{84} $
B) $ \frac{1}{21} $
C) $ \frac{5}{84} $
D) None of these
Show Answer
Answer:
Correct Answer: C
Solution:
Total number of ways in which 3 balls can be drawn are $ {}^{9}C_3=84. $
Since the drawn balls can’t be of red colour, as these are 2 in numbers.
Therefore favourable number of ways $ ={}^{3}C_3+{}^{4}C_3. $
Hence the required probability $ =\frac{5}{84}. $