Analysis and Approaches for IBDP Maths Ebook 1 | Seite 242

Your Practice Set – Analysis and Approaches for IBDP Mathematics
78
Paper 1 Section A – Probability with Venn diagrams
Example
In a group of 25 students, 11 take arts and 14 take business. 6 students take both arts and
business, as shown in the following Venn diagram. The values p and q represent
numbers of students.
(a)
Find the value of
(b)
(i) p ;
(ii) q .
A student is selected at random. Find the probability that he takes arts but not
business.
[4]
[2]
Solution
(a) (i) p �6 � 11
(M1) for valid approach
p � 5
A1 N2
(b)
(ii) 5�14 � q � 25
(M1) for valid approach
q � 6
A1 N2
The required probability
5
� (M1) for valid approach
25
1
� A1 N2
5
[4]
[2]
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