Mathematics 0580 · IGCSE · Probability of combined events

Probability of combined events — practice question

Kiah takes part in a game in which a coin is thrown onto a circular board. Points depend on the region where the coin lands. If the coin lands on a line or fails to reach the board, then 0 points are awarded. The diagram shows concentric regions labelled 20 in the centre, 10 in the middle, and 5 on the outside. The table gives the probabilities of Kiah scoring points on the board from one throw.
(a)[2]

Find the value of $x$ in the table.

(b)[1]

Work out the expected number of times she scores 5 points.

(c(i))[2]

Calculate the probability that her first throw results in either 5 or 0.

(c(ii))[2]

Calculate the probability that her first throw scores 0 and her second throw scores 5.

(c(iii))[3]

Calculate the probability that the total from her two throws is 15 points.

(d)[5]

Calculate the probability that the total from her three throws is 10 points.

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