year 8 maths

Chapter review
59
Extended-response questions
1 Two bus companies have different pricing structures.
Company A: $120 call-out fee, plus $80 per hour
Company B: $80 call-out fee, plus $100 per hour
a Write an expression for the total cost $A of travelling n hours with company A .
b Write an expression for the total cost $B of travelling for n hours with company B .
c Hence, state the cost of travelling for three hours with each company.
d For how long would you need to hire a bus to make company A the cheaper option?
e A school principal cannot decide which bus company to choose and hires three buses from
company A and two buses from company B . Give an expanded expression to find the total cost for
the school to hire the five buses for n hours.
f If the trip lasts for five hours, how much does it cost to hire the five buses for this period of time?
2 Consider the floor plan shown.
y
x
a Write an expanded expression for the floor’s area in terms of x and y .
b Hence, find the floor’s area if x = 6 metres and y = 7 metres.
c Write an expression for the floor’s perimeter in terms of x and y .
d Hence, find the floor’s perimeter if x = 6 metres and y = 7 metres.
e Another floor plan is shown below. Write an expression for the floor’s area and an expression for
its perimeter.
y
x
f i By how much does the area differ in the two floor plans?
ii By how much does the perimeter differ in the two floor plans?
Cambridge Maths NSW
Stage 4 Year 8 Second edition
ISBN 978-1-108-46627-1 © Palmer et al. 2018
Cambridge University Press
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