Mathematics 9709 · AS & A Level · Linear combinations of random variables

Linear combinations of random variables — practice question

(i)[3]

Four fair six-sided dice, with faces numbered $1, 2, 3, 4, 5, 6$, are rolled. Determine the probability that the four shown numbers add to $5$.

(ii)[4]

Four fair six-sided dice, with faces numbered $1, 2, 3, 4, 5, 6$, are rolled on $7$ separate occasions. Determine the probability that the numbers shown on the four dice add to $5$ on exactly $1$ or $2$ of the $7$ occasions.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: A single correct outcome is given (for example $1122, 1212, 2112$ etc.)

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