WAEC - Mathematics (2019 - No. 33)
A box contains 2 white and 3 blue identical balls. If two balls are picked at random from the box, one after the other with replacement, what is the probability that they are of different colours?
\(\frac{2}{3}\)
\(\frac{3}{5}\)
\(\frac{7}{20}\)
\(\frac{12}{25}\)
설명
(\(\frac{2}{5} \times \frac {3}{5}) + (\frac{3}{5} \times \frac{2}{5})\)
\(\frac{6}{25} + \frac{6}{25} = \frac{12}{25}\)