WAEC - Further Mathematics (2013 - No. 33)
Two out of ten tickets on sale for a raffle draw are winning tickets. If a guest bought two tickets, what is the probability that both tickets are winning tickets?
\(\frac{1}{80}\)
\(\frac{1}{45}\)
\(\frac{1}{20}\)
\(\frac{1}{10}\)
説明
P(winning) = \(\frac{2}{10}\)
P(both tickets winning) = \(\frac{2}{10} \times \frac{1}{9} = \frac{1}{45}\)