A factory makes chocolates. $30\%$ of them are covered in gold foil, $25\%$ are covered in red foil and the rest are left unwrapped. Indigo picks $8$ chocolates at random from the production line.
(a)[3]
Find the probability that she gets no more than $2$ chocolates wrapped in red foil.
(b)[2]
Jake chooses chocolates one at a time at random from the production line. Find the probability that the first time he gets a chocolate wrapped in red foil is before the $7$th choice.
(c)[5]
Keifa chooses chocolates one at a time at random from the production line. Find the probability that the second chocolate chosen is the first one wrapped in gold foil given that the fifth chocolate chosen is the first unwrapped chocolate.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Binomial terms used for $P(X=0,1,2)$ or the equivalent complement” …