A bag contains 3 red and 2 white identical balls. lf 2 balls are picked at random from the bag, one after the other and with replacement, find the probability that they are of different colours

  • A \(\frac{36}{625}\)
  • B \(\frac{16}{625}\)
  • C \(\frac{12}{25}\)
  • D \(\frac{13}{25}\)
waec 2004mathematics

The correct answer is C. \(\frac{12}{25}\)

Prob(RW or WR) = Prob(RW) + Prob(WR)

\(Prob(R) = \frac{3}{5}:Prob(W) = \frac{2}{5}\\

Prob(RW\hspace{1mm}or\hspace{1mm}WR)=\frac{3}{5}\times\frac{2}{5}+\frac{2}{5}\times \frac{3}{5}\\

\frac{6}{25}+\frac{6}{25}=\frac{12}{25}\)

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