Apps. and Interpretation for IBDP Maths Ebook 1 | Page 26

Your Practice Set – Applications and Interpretation for IBDP Mathematics
5
Paper 1 – Linear Functions
Example
The relationship between F , the temperature in degrees Fahrenheit, and C , the
temperature in degrees Celsius, is given by F �mC �32.
(a) Interpret what m represents.
[1]
It is given that the temperature in 25 degrees Celsius is equivalent to the temperature in
77 degrees Fahrenheit.
(b) Find the value of m .
(c)
Find the value of 122 degrees Fahrenheit in degrees Celsius.
[2]
[2]
Solution
(a)
m represents the rate of change of degrees
Fahrenheit per 1 degree Celsius increase. A1 N1
(b) 77 �m (25) �32
(M1) for substitution
(c)
45 � 25m
9
m �
5
A1 N2
9
122 � C �32
5
(M1) for substitution
9
90 � C
5
C � 50
Therefore, the temperature is 50 degrees Celsius. A1 N2
[1]
[2]
[2]
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