BITSAT2014MathematicsProbabilityActual
A bag contains 5 brown and 4 white socks. A man pulls out 2 socks. Find the probability that they are of the same colour.
Options
- A4 9
- B2 9
- C5 9
- D7 9
Correct answer
A. 4 9
Step-by-step solution
Let A event of two socks being brown. B event of two socks being white. Then aligned & P(A)= 5 2 9 2 = 5.4 9.8 = 5 18 , P ( B ) &= ⁴ C ₂ ⁹ C ₂ = 4.3 9.8 = 3 18 aligned Now, since A and B are mutually exclusive events, so required probability = P ( A )+ P ( B )= 5 18 + 3 18 = 4 9