User interface language: English | Español

Date November 2016 Marks available 2 Reference code 16N.1.SL.TZ0.T_12
Level Standard Level Paper Paper 1 Time zone Time zone 0
Command term Complete Question number T_12 Adapted from N/A

Question

On a work day, the probability that Mr Van Winkel wakes up early is 4 5 .

If he wakes up early, the probability that he is on time for work is p .

If he wakes up late, the probability that he is on time for work is 1 4 .

The probability that Mr Van Winkel arrives on time for work is 3 5 .

Complete the tree diagram below.

N16/5/MATSD/SP1/ENG/TZ0/12.a

[2]
a.

Find the value of p .

[4]
b.

Markscheme

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

N16/5/MATSD/SP1/ENG/TZ0/12.a/M     (A1)(A1)     (C2)

 

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

 

[2 marks]

a.

4 5 p + 1 5 × 1 4 = 3 5      (A1)(ft)(M1)(M1)

 

Note:     Award (A1)(ft) for two correct products from part (a), (M1) for adding their products, (M1) for equating the sum of any two probabilities to 3 5 .

 

( p = )   11 16   ( 0.688 ,   0.6875 )    (A1)(ft)     (C4)

 

Note:     Award the final (A1)(ft) only if 0 p 1 . Follow through from part (a).

 

[4 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
Show 306 related questions
Topic 4—Statistics and probability

View options