AP EAMCET2007MathematicsProbability
A bag contains 6 white and 4 black balls. Two balls are drawn at random. The probability that they are of the same colour, is
Options
- A1 / 15
- B2 / 5
- C4 / 15
- D7 / 15
Correct answer
D. 7 / 15
Step-by-step solution
The number of ways to select 2 balls out of 10 = ¹⁰ C₂ Number of ways to select 2 balls both white = ^6 C₂ . Number of ways to select 2 balls both black = ^4 C₂ The required probability = ^6 C₂+ ^4 C₂ ¹⁰ C₂ = 7 15