(a)[2]
Show that $P(X = 3)$ equals $\frac{6}{35}$.
(b)[4]
Draw up a probability distribution table for $X$.
(c)[3]
Find the value of $\mathrm{Var}(X)$.
Mathematics 9709 · AS & A Level · Discrete random variables
Discrete random variables — practice question
Sharma is aware that her cupboard contains 3 tins of carrots, 2 tins of peas and 2 tins of sweetcorn. Every tin has the same shape and size, but all the labels have been removed, so Sharma cannot tell what is in any tin. Sharma wants carrots for her meal, so she opens the tins one at a time, chosen at random, until she opens a tin of carrots. The random variable $X$ represents the number of tins she has to open.
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