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Date May 2017 Marks available 2 Reference code 17M.2.SL.TZ2.S_B10
Level Standard Level Paper Paper 2 Time zone Time zone 2
Command term Find Question number S_B10 Adapted from N/A

Question

The following table shows a probability distribution for the random variable X , where E ( X ) = 1.2 .

M17/5/MATME/SP2/ENG/TZ2/10

A bag contains white and blue marbles, with at least three of each colour. Three marbles are drawn from the bag, without replacement. The number of blue marbles drawn is given by the random variable X .

A game is played in which three marbles are drawn from the bag of ten marbles, without replacement. A player wins a prize if three white marbles are drawn.

Jill plays the game nine times. Find the probability that she wins exactly two prizes.

Markscheme

valid approach     (M1)

eg B ( n ,   p ) ,   ( n r ) p r q n r ,   ( 0.167 ) 2 ( 0.833 ) 7 ,   ( 9 2 )

0.279081

0.279     A1     N2

[2 marks]

Examiners report

[N/A]

Syllabus sections

Topic 4—Statistics and probability » SL 4.5—Probability concepts, expected numbers
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Topic 4—Statistics and probability

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