Analysis and Approaches for IBDP Maths Ebook 1 | Seite 227

Front Page
(a) (i) Write down the median number of hours worked by workers.
(ii) Write down the number of workers who worked 30 hours or less.
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The city paid each of the workers $20 per hour for the first 30 hours worked, and $30 per
hour for each hour they worked after the first 30 hours.
(b)
Find the amount of money a worker earned for working
(i)
25 hours;
(ii)
35 hours.
(c) Find the number of workers who earned less than or equal to $200.
(d) Only 10 workers earned more than $k . Find the value of k .
The data above was obtained from a survey. A manager arranged the worker IDs in
ascending order and then asked every 10th worker on the list.
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[3]
[4]
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(e)
Identify the sampling technique used.
[1]
Solution
(a) (i) 20 hours A2 N2
(ii) 55 A1 N1
(b) (i) The amount of money
� (20)(25)
� $500
A1 N1
[3]
(c)
(ii) The amount of money
� (20)(30) � (30)(35 � 30)
(M1)(A1) for correct formula
� $750
A1 N3
[4]
The number of working hours
200
�
20
(M1) for valid approach
� 10
Thus, the number of workers is 15. A2 N3
[3]
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