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Date May 2017 Marks available 3 Reference code 17M.1.SL.TZ1.T_7
Level Standard Level Paper Paper 1 (with calculator from previous syllabus) Time zone Time zone 1
Command term Find Question number T_7 Adapted from N/A

Question

Sara regularly flies from Geneva to London. She takes either a direct flight or a non-directflight that goes via Amsterdam.

If she takes a direct flight, the probability that her baggage does not arrive in London is 0.01.
If she takes a non-direct flight the probability that her baggage arrives in London is 0.95.

The probability that she takes a non-direct flight is 0.2.

M17/5/MATSD/SP1/ENG/TZ1/07

Complete the tree diagram.

[3]
a.

Find the probability that Sara’s baggage arrives in London.

[3]
b.

Markscheme

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

M17/5/MATSD/SP1/ENG/TZ1/07.a/M     (A1)(A1)(A1)     (C3)

 

 

Note:     Award (A1) for each correct pair of probabilities.

 

[3 marks]

a.

0.8 × 0.99 + 0.2 × 0.95     (A1)(ft)(M1)

 

Note:     Award (A1)(ft) for two correct products of probabilities taken from their diagram, (M1) for the addition of their products.

 

= 0.982   ( 98.2 % ,   491 500 )     (A1)(ft)     (C3)

 

Note:     Follow through from part (a).

 

[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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