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Date May 2017 Marks available 1 Reference code 17M.1.SL.TZ2.T_2
Level Standard Level Paper Paper 1 Time zone Time zone 2
Command term Write down Question number T_2 Adapted from N/A

Question

All the children in a summer camp play at least one sport, from a choice of football ( F ) or basketball ( B ). 15 children play both sports.

The number of children who play only football is double the number of children who play only basketball.

Let x be the number of children who play only football.

There are 120 children in the summer camp.

Write down an expression, in terms of x , for the number of children who play only basketball.

[1]
a.

Complete the Venn diagram using the above information.

[2]
b.

Find the number of children who play only football.

[2]
c.

Write down the value of n ( F ) .

[1]
d.

Markscheme

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

1 2 x     (A1)     (C1)

[1 mark]

a.

   (A1)(A1)(ft)     (C2)

 

Notes:     Award (A1) for 15 placed in the correct position, award (A1)(ft) for x and their 1 2 x placed in the correct positions of diagram. Do not penalize the absence of 0 inside the rectangle and award at most (A1)(A0) if any value other than 0 is seen outside the circles. Award at most (A1)(A0) if 35 and 70 are seen instead of x and their 1 2 x .

 

[2 marks]

b.

x + 1 2 x + 15 = 120 or equivalent     (M1)

 

Note:     Award (M1) for adding the values in their Venn and equating to 120 (or equivalent).

 

( x = )   70     (A1)(ft)     (C2)

 

Note:     Follow through from their Venn diagram, but only if the answer is a positive integer and x is seen in their Venn diagram.

 

[2 marks]

c.

85     (A1)(ft)     (C1)

 

Note:     Follow through from their Venn diagram and their answer to part (c), but only if the answer is a positive integer and less than 120.

 

[1 mark]

d.

Examiners report

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

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
Topic 4—Statistics and probability

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