year 8 maths

4J
Calculating percentage change, profit and loss
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Exercise 4J
UNDERSTANDING AND FLUENCY
1–4, 5(½), 6, 7 3, 4, 5(½), 6, 7
6, 7
1 Calculate the profit made in each of the following situations.
a Cost price = $14, Sale price = $21
b Cost price = $75, Sale price = $103
c Cost price = $25.50, Sale price = $28.95
d Cost price = $499, Sale price = $935
2 Calculate the loss made in each of the following situations.
a Cost price = $22, Sale price = $9
b Cost price = $92, Sale price = $47
c Cost price = $71.10, Sale price = $45.20
d Cost price = $1121, Sale price = $874
3 Which of the following is the correct formula for working out percentage change?
change
original value
A % Change =
B % Change =
original value
change
C % Change = change × 100% D % Change =
4 The formula used for calculating percentage loss is: % Loss =
× 100%
change
original value × 100%
loss
cost price × 100% .
Which of the following would therefore be the formula for calculating the percentage discount?
A % Discount = discount
cost price × 100%
C % Discount = discount × 100%
cost price
B % Discount = × 100%
discount
D % Discount = discount × cost price
100%
Example 30
5 Find the percentage change (profit or loss) when:
a $20 becomes $36
b $10 becomes $13
c $40 becomes $30
d $25 becomes $21
e $12 becomes $20
f $8 becomes $11
g $6 becomes $4
h $150 becomes $117
6 Find the percentage change (increase or decrease) when:
a 15°C becomes 18°C
b 18°C becomes 15°C
c 4°C becomes 24°C
d 12°C becomes 30°C
7 Find the percentage change in population when:
a a town of 4000 becomes a town of 5000
b a city of 750 000 becomes a city of 900 000
c a country of 5 000 000 becomes a country of 12 000 000
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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