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Date May 2017 Marks available 3 Reference code 17M.2.AHL.TZ1.H_1
Level Additional Higher Level Paper Paper 2 Time zone Time zone 1
Command term Find Question number H_1 Adapted from N/A

Question

Consider two events A and B such that P ( A ) = k ,  P ( B ) = 3 k ,  P ( A B ) = k 2 and P ( A B ) = 0.5 .

Calculate k ;

[3]
a.

Find P ( A B ) .

[3]
b.

Markscheme

* This question is from an exam for a previous syllabus, and may contain minor differences in marking or structure.

use of P ( A B ) = P ( A ) + P ( B ) P ( A B )      M1

0.5 = k + 3 k k 2      A1

k 2 4 k + 0.5 = 0

k = 0.129      A1

 

Note:     Do not award the final A1 if two solutions are given.

 

[3 marks]

a.

use of P ( A B ) = P ( B ) P ( A B ) or alternative     (M1)

P ( A B ) = 3 k k 2      (A1)

= 0.371      A1

[3 marks]

b.

Examiners report

[N/A]
a.
[N/A]
b.

Syllabus sections

Topic 4—Statistics and probability » SL 4.6—Combined, mutually exclusive, conditional, independence, prob diagrams
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Topic 4—Statistics and probability

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