A box contain 2 white and 3 blue identical balls. If two balls are picked at random, one after the other, without replacement, what is the probability of pi...

A box contain 2 white and 3 blue identical balls. If two balls are picked at random, one after the other, without replacement, what is the probability of picking two balls of different colours?

Answer Details

The probability of picking two balls of different colours is the probability of picking one white ball and one blue ball, because there are no other colours in the box. The probability of picking a white ball on the first draw is 2/5, since there are 2 white balls out of 5 total balls. After one white ball has been removed, there are 4 balls left, including 2 blue balls. Therefore, the probability of picking a blue ball on the second draw is 2/4 or 1/2. The probability of picking a white ball on the first draw and a blue ball on the second draw is thus: \(\frac{2}{5} * \frac{1}{2} = \frac{1}{5}\) There is also a probability of picking a blue ball on the first draw and a white ball on the second draw, which is: \(\frac{3}{5} * \frac{2}{4} = \frac{3}{10}\) Therefore, the total probability of picking two balls of different colours is: \(\frac{1}{5} + \frac{3}{10} = \frac{1}{5} + \frac{2}{5} = \frac{3}{5}\) So the answer is \(\frac{3}{5}\).