Mathematics 9709 · AS & A Level · Discrete random variables
Discrete random variables — practice question
The bag has $5$ yellow marbles and $4$ green marbles. Three marbles are chosen at random from the bag, without replacement.
(a)[3]
Show that the probability that exactly one of the marbles is yellow is $\frac{5}{14}$.
(b)[3]
Draw up the probability distribution table for $X$, where the random variable $X$ is the number of yellow marbles selected.
(c)[1]
Find the value of $\text{E}(X)$.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Set up the probability for one yellow outcome using suitable combinations or sequential probabilities” …