WAEC - Mathematics (2005 - No. 16)
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
\(\frac{1}{10}\)
\(\frac{3}{10}\)
\(\frac{9}{20}\)
\(\frac{11}{20}\)
설명
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)\(=frac{1}{4}\times \frac{2}{5}=\frac{1}{10}\)
Prob.(James pass) \(=frac{3}{5}\) Prob.(James fail) \(=1-frac{3}{5}=\frac{2}{5}\)
Prob(both boys fail)\(=frac{1}{4}\times \frac{2}{5}=\frac{1}{10}\)