Apps. and Interpretation for IBDP Maths Ebook 1 | Page 66

Your Practice Set – Applications and Interpretation for IBDP Mathematics
18
Paper 1 – Real Life Problems
Example
Josie pays money into a saving scheme each year, for 50 years. In the first year she pays
$4100, and her payments increases by the same amount each year. It is given that she
pays $4350 in the second year.
(a)
(b)
Find the amount that Josie will pay in the 15th year.
Find the exact total amount that Josie will pay in over the 50 years.
[3]
[3]
Solution
(a) d �4350 � 4100
(M1) for finding d
d � 250
The required amount
� u 15
(M1) for valid approach
(b)
� 4100 � (15 � 1)(250)
� $7600
A1 N3
The total amount
� S 50
(M1) for valid approach
� 50 � 2(4100) � (50 � 1)(250) �
(A1) for substitution
2
� $511250
A1 N3
[3]
[3]
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