The probability that John and James pass an examination are 3/4 and 3/5 respectively, find the probability of both boys failing the examination

  • A \(\frac{1}{10}\)
  • B \(\frac{3}{10}\)
  • C \(\frac{9}{20}\)
  • D \(\frac{11}{20}\)
waec 2005mathematics

The correct answer is A. \(\frac{1}{10}\)

Prob.(John pass)\(=frac{3}{4}\) prob.(John fail) \(=1-frac{3}{4}=\frac{1}{4}\)

Prob.(James pass) \(=frac{3}{5}\) Prob.(James fail) \(=1-frac{3}{5}=\frac{2}{5}\)

Prob(both boys fail)\(=frac{1}{4}\times \frac{2}{5}=\frac{1}{10}\)

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