9709 P52 - Nov 2020 - Q2
2893
A bag contains 5 red balls and 3 blue balls. Sadie takes 3 balls at random from the bag, without replacement. The random variable X represents the number of red balls that she takes.
(a) Show that the probability that Sadie takes exactly 1 red ball is \(\frac{15}{56}\).
(b) Draw up the probability distribution table for X.
(c) Given that \(E(X) = \frac{15}{8}\), find \(\text{Var}(X)\).
