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Date May 2022 Marks available 2 Reference code 22M.1.SL.TZ2.2
Level Standard Level Paper Paper 1 Time zone Time zone 2
Command term Find Question number 2 Adapted from N/A

Question

A group of 130 applicants applied for admission into either the Arts programme or the Sciences programme at a university. The outcomes of their applications are shown in the following table.

An applicant is chosen at random from this group. It is found that they were accepted into the programme of their choice.

Find the probability that a randomly chosen applicant from this group was accepted by the university.

[1]
a.

Find the probability that the applicant applied for the Arts programme.

[2]
b.

Two different applicants are chosen at random from the original group.

Find the probability that both applicants applied to the Arts programme.

[3]
c.

Markscheme

17+25130= 42130  2165, 0.323076           A1

 

[1 mark]

a.

1717+25= 1742  0.404761           A1A1

 

Note: Award A1 for correct numerator and A1 for correct denominator.
Award A1A0 for working of 17/130their answer to (a) if followed by an incorrect answer.

 

[2 marks]

b.

41130×40129           A1M1


Note: Award A1 for two correct fractions seen, M1 for multiplying their fractions.

 

=1640167700.0978  0.0977936, 1641677           A1

 

[3 marks]

c.

Examiners report

Candidates are reasonably proficient at calculating simple probabilities from a table.

a.

Several candidates did not consider the condition, with some merely finding the probability of an applicant applying for Arts programme with no condition, some considering those who were accepted into Arts with no condition, and some finding the probability of being accepted into Arts given the condition that they applied for Arts.

b.

Only a few candidates recognized dependent events, with most calculating as if the events were independent.

c.

Syllabus sections

Topic 4—Statistics and probability » SL 4.5—Probability concepts, expected numbers
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Topic 4—Statistics and probability » SL 4.6—Combined, mutually exclusive, conditional, independence, prob diagrams
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