Apps. and Interpretation for IBDP Maths Ebook 1 | Page 270

Your Practice Set – Applications and Interpretation for IBDP Mathematics
(c) (i) The required probability
�P( F�
J)
�P( J | F) � P( F)
(M1) for valid approach
�0.75� 0.58
(A1) for substitution
� 0.435
A1 N3
(ii) P( F � J) � P( F�� J) � P( J)
(M1) for valid approach
0.435 � P( F�� J) � 0.8
P( F��J) � 0.365
Thus, the required probability is 0.365. A1 N2
(iii) P( F) �P( F�) � 1
0.58 �P( F�) � 1
(A1) for substitution
P( F�) � 0.42
Thus, the required probability is 0.42. A1 N2
(iv)
The required probability
� P( J | F�)
P( F��
J)
�
P( F�)
0.365
�
0.42
(A1) for substitution
� 0.869047619
� 0.869
A1 N2
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