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AA Pearson Maths 9 EE-01.fm Page 2 Tuesday, April 24, 2012 10:46 AM
1
Financial
mathematics
Recall 1
Prepare for this chapter by attempting the following questions. If you have difficulty with
a question, go to Pearson Places and download the Recall Worksheet from Pearson Reader.
1 Convert the following fractions to decimals.
Wo
r ks h e e t R 1. 1
321
(c) ------------------
57
(b) -----------
17
(a) --------
100 000
1000
100
2 Convert the following fractions to decimals. If the decimal is a recurring decimal, use the
r ks h e e t R 1. 2
appropriate notation.
6
40
8
25
(d) 1---
-----(c) 23
(b) 9---
-----(a) 16
-----(e) 10
(f)
11
s
Wo
5
--7
Wo
r ks h e e t R 1. 3
(a) 0.79
(b) 0.003
(c) 0.014
4 Evaluate the following.
r ks h e e t R 1. 4
(a) 5.8 + 2.9
(b) 12.7 − 3.6
(d) 1.065
(e) 10.140
(c) 5.2 × 1.5
(f) 0.0902
(d) 6.2 ÷ 0.03
pa
Wo
ge
3 Convert the following decimals to fractions in simplest form.
5 Convert the following fractions and decimals to percentages. (Round your answers to two
r ks h e e t R 1. 5
decimal places, if necessary.)
-----(a) 14
20
(b) 0.91
(c) 0.032
pl
e
Wo
(c) 6.7%
(b) 30%
(c) 2.5%
-----(d) 23
28
6 Write the following percentages as fractions in simplest form.
Wo
r ks h e e t R 1. 6
(a) 85%
(b) 22%
(d) 1--- %
2
Wo
r ks h e e t R 1. 7
m
7 Write the following percentages in decimal form.
(a) 49%
(d) 370%
Wo
r ks h e e t R 1. 8
Sa
8 Calculate the following:
(a) 5--- of 90 m
6
(b) 3--- of 105 kg
------ of $25 600
(c) 11
(b) 10% of 63.5 km
(c) 22% of 18.1 cm
4
10
9 Find:
Wo
r ks h e e t R 1. 9
(a) 5% of 20 m
After completing this chapter you will be able to:
perform percentage calculations
calculate profit, loss, discount, mark up, selling price and cost price
calculate incomes earned under a variety of payment systems
understand some of the employment conditions laid out by awards and agreements
perform simple interest calculations
describe different methods of payment (such as credit cards), and perform calculations
associated with them
• calculate the cost of using resources such as electricity, gas and water
• calculate the cost of using a mobile phone.
•
•
•
•
•
•
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mathematics 9 essentials edition
AA Pearson Maths 9 EE-01.fm Page 3 Tuesday, April 24, 2012 10:46 AM
1.1
1.1
Percentages review
Need to Know
Fraction
1--2
1--4
3--4
1--3
2--3
1----10
1--5
1----20
1-------100
Decimal
0.5
0.25
0.75
0.3˙
0.6˙
0.1
0.2
0.05
0.01
50%
25%
75%
10%
20%
5%
1%
Percentage
33 1--- % 66 2--- %
3
3
Calculate the percentages of the given amounts:
(b) 27.5% of $300
(a) 35% = 30% + 5%
= 3 × 10% + 5%
5% of 62
= (10% of 62) ÷ 2
= 6.2 ÷ 2
= 3.1
Sa
3 × 10% + 5%
= (3 × 6.2) + 3.1
= 18.6 + 3.1
= 21.7
(a)
35% of 62
= 35% × 62
35
= --------- × 62 or
100
m
10% of 62
= 62 ÷ 10
= 6.2
Method 2: Fraction or decimal multiplication
pl
e
Method 1: Use basic percentages
pa
(a) 35% of $62
1
ge
s
Worked Example 1
35% of $62 = $21.70
0.35 × 62
7
35
--------- × 62
------100
1
20
=
31
7- 62
-----× ------20
1
10
7 31
= ----- × ----10 1
217
= ------10
= 21.7
35% of $62 = $21.70
1 • Financial mathematics
3
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1.1
(b) 27.5% = 25% + 2.5%
25% of 300
= 300 ÷ 4
= 300 ÷ 2 ÷ 2
= 150 ÷ 2
= 75
(b)
2.5% = 25% ÷ 10
= 75 ÷ 10
= 7.5
27.5% of 300
= 27.5% × 300
27.5
= ---------- × 300 or
100
= 27.5 × 3
= 82.5
0.275 × 300
27.5% of $300 = $82.50
25% + 2.5%
= 75 + 7.5
= 82.5
27.5% of $300 = $82.50
Worked Example 2
2
s
Increase or decrease the following amounts by the given percentages. If necessary, round
decimal answers to two decimal places.
1.65 × 420 = 693
(b) (100 − 13.6)% = 86.4%
= 0.864
pa
(a) (100 + 65)% = 165%
= 1.65
(b) Decrease 87 kg by 13.6%
ge
(a) Increase $420 by 65%
pl
e
$420 increased by 65% is $693.
0.864 × 87 = 75.168
87 kg decreased by 13.6% is 75.17 kg.
Worked Example 3
m
3
Round your answers to the following questions to one decimal place.
Sa
(a) Tyler kicked 13 goals from 18 shots at goal. Calculate his kicking accuracy as a
percentage.
(b) A packet of ‘Chocky’ biscuits is on sale for $2.35, a saving of 57c. Write the saving as
a percentage of the original price.
Method 1: Fraction multiplication
(a)
13
----- × 100
--------- %
18
1
13 50100
= ----- × --------1
9 18
650
= ----------9
2
= 72 ---% or 72.2˙ %
9
Tyler’s kicking accuracy is 72.2% (1 d.p.).
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mathematics 9 essentials edition
Method 2: Convert to a decimal, then multiply
13
(a) ----- = 13 ÷ 18 = 0.7222…
18
0.7222… × 100% = 72.2222…%
Tyler’s kicking accuracy is 72.2%
(1 d.p.).
AA Pearson Maths 9 EE-01.fm Page 5 Tuesday, April 24, 2012 10:46 AM
1.1
(b) $2.35 + $0.57 = $2.92
(b) $2.35 + $0.57 = $2.92
0.57
----------- × 100
--------- %
2.92
1
57
= ----------- %
2.92
= 19.520 54…%
0.57
----------- = 0.57 ÷ 2.92 = 0.1952…
2.92
0.1952… × 100% = 19.52…%
The saving is 19.5% of the original price
(1 d.p.).
The saving is 19.5% of the original price
(1 d.p.).
.
1 1 Percentages review
Answers
page 398
Fluency
s
1 Calculate the percentages of the given amounts. If necessary, round decimal answers to
(a) 25% of $40
(b) 45% of $50
(d) 11% of 60 L
(e) 66% of 400 m
(g) 9% of 20 kg
(h) 59% of 74 kg
(j) 0.5% of $3500
(k) 12.5% of 1500 m
1
5
(c) 30% of $150
(f) 77% of 35 kg
(i) 88% of 60 L
pa
3
4
(n) 6 --- % of $90
(l) 7.2% of 15 L
2
3
(o) --- % of $200 000
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(m) 5 --- % of $17 000
2 Increase or decrease the following amounts by the given percentages. If necessary, round
decimal answers to two decimal places.
(i) 50%
m
(a) Increase 240 by:
1
ge
two decimal places.
(ii) 35%
(iii) 8%
(iv) 140%
(ii) 75%
(iii) 46%
(iv) 98%
(ii) 260%
(iii) 7.5%
(iv) 6 --- %
(iii) 6.3%
(iv) 3 --- %
2
(b) Decrease 5700 by:
Sa
(i) 20%
(c) Increase $64.15 by:
(i) 10%
(d) Decrease 9.8 seconds by:
(i) 50%
(ii) 13%
3
4
1
3
3 Round your answers to the following questions to one decimal place.
(a) Ash kicked nine goals from 13 shots at goal. Calculate Ash’s percentage kicking
3
accuracy.
(b) A jar of ‘Nuttie’s’ peanut butter is on sale for $3.18, a saving of 64 cents. Write the
saving as a percentage of the original price.
(c) Maryam had 22 shots at the netball goals and got 14 in. Calculate Maryam’s
percentage shooting accuracy.
(d) A box of ‘Crunchy-Bix’ cereal has been reduced by $1.02 to $4.37. Calculate the
percentage saving based on the original cost price.
(e) Raf got 76 of 114 serves into the tennis court. Calculate the percentage accuracy of
Raf’s serve.
1 • Financial mathematics
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AA Pearson Maths 9 EE-01.fm Page 6 Tuesday, April 24, 2012 10:46 AM
1.1
(f) A tin of ‘Beanz’ baked beans is on sale for $1.17, a saving of 32 cents. Write the saving
as a percentage of the original price.
(g) Brett bowled a cricket ball at a set of stumps 54 times. He hit the stumps 41 times.
Calculate Brett’s stump-hitting accuracy as a percentage of the number of balls bowled.
(h) A tub of ‘Yo-Cal’ yoghurt has been reduced by 74 cents to $2.11. Calculate the
percentage saving based on the original cost price.
Understanding
4 This is the nutritional label
from a packet of muesli bars.
The ‘serving size’ is one bar,
which has a mass of 20 g.
(a) Use the information in
s
the ‘Quantity per serving’
column to calculate the
percentage mass of the
muesli bar that is:
(ii) protein
(iii) fat (total).
pa
(b) Sugar is a type of carbohydrate.
ge
(i) carbohydrate
(i) What percentage of the mass of a muesli bar is sugar?
(ii) What percentage of the carbohydrate mass is sugar?
pl
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Answer to one demical place.
5 The label on a bottle of tropical fruit juice says:
78%
15.5%
4.5%
2%
m
Pineapple juice:
Orange juice:
Passionfruit juice:
Guava juice:
Sa
There is 2.5 L of juice in the bottle. Calculate the volume of each type of juice, rounding
answers to the nearest mL if necessary.
6 Approximately 65%of the mass of an adult human is water. Akira weighs 58 kg. How
much of Akira’s mass is water, to the nearest 100 g?
7 Stuart earns $1023.87 a week working as a plumber. He receives a weekly pay increase of 3.5%.
(a) Calculate Stuart’s new weekly wage.
(b) How much more is Stuart now earning per week?
8 Charlotte is a runner whose personal best time for her favourite race is 3 min 34 seconds.
(a) Charlotte wants to decrease her time by 4%. How many seconds is this?
(b) At the state titles, Charlotte lowered her time by 6.9 seconds. What percentage
improvement is this, correct to two decimal places?
9 There are two male and seven female gorillas in a zoo enclosure.
(a) What fraction of the gorillas are female?
(b) What percentage of the gorillas are male?
(c) One extra female is added to the enclosure. Recalculate your answers to (a) and (b).
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mathematics 9 essentials edition
AA Pearson Maths 9 EE-01.fm Page 7 Tuesday, April 24, 2012 10:46 AM
1.1
10 Copy and complete the following table.
Common fraction
Decimal fraction
Percentage
1
--2
(a)
0.45
(b)
72%
(c)
5--4
(d)
0.56
(e)
12.5%
(f)
11 Approximately 7--- of an iceberg lies under water. The mass of the iceberg is 150 000 tonnes.
8
(a) What mass of the iceberg is under water?
(b) What percentage of the whole mass is this?
12 At the end of the first week of trading on the share market, shares in Jaydeep’s company
had increased by 17.5%. The shares were worth $3.40 each at the beginning of the week.
s
(a) What is the value of a share now?
ge
(b) At the end of the second week, the share price had decreased by 9% compared with
its price at the beginning of that week. Calculate the value of one share at the end of
the second week.
pa
(c) Calculate the overall increase or decrease at the end of the 2 weeks as a percentage
of the original price of $3.40, correct to two decimal places.
Reasoning
5
pl
e
13 In her Drama class, 3--- of Anita’s overall mark is allocated to the practical exam and the
remaining 2--- is allocated to the written exam. Anita scored 82% in her practical exam and
5
76% in the written exam. Calculate Anita’s overall percentage for the subject, correct to
1 decimal place.
m
14 The local newspaper had the following headline: ‘Prime Minister’s approval rating 67%’.
15 (a)
Sa
The article stated that the newspaper had surveyed all 180 000 of its readers, of which 14%
had responded. Of those who responded, 67% said that they thought the Prime Minister
was doing a good job. How many people actually said this?
(i) Increase 100 by 20%.
(ii) Now decrease the answer obtained by 20%.
(b)
(i) Increase 300 by 30%.
(ii) Now decrease the answer obtained by 30%.
(c) Explain why you do not arrive back at the starting number after an increase and
decrease by the same percentage.
Open-ended
16 Write three whole numbers that when increased by 140% give an answer between 100
and 200.
17 Trent is looking to buy a new iPod. In one store, the iPod was on sale for $258, an
advertised saving of $31. In another store, the same model iPod had a marked price
of $299, but a sale sticker next to it said ‘take 25% off the marked price’. Trent decided
that $31 sounded like a better saving than 25% and bought the iPod from the first store.
(a) Was this the right choice in terms of saving money? Explain why or why not.
(b) Describe a simple calculation Trent could have done while standing in the shop that
could have helped him make a more effective decision.
1 • Financial mathematics
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1.1
Problem
Problem
oblem solving
Age-old dilemmas
1 My mother is three times my age.
2 Harry, Larry and Garry are three
brothers who all go to secondary
school.
My sister is 75% of my age and 15% of
my grandmother’s age.
My father is 40, 4 years older than my
mother.
Find my age, my grandmother’s age
and my sister’s age.
Harry and Larry are an exact number
of years apart. They have their
birthdays on the same day. Garry’s
birthday is on a different day.
Harry is 80% of Larry’s age.
Garry is 110% of Larry’s age.
Strategy options
How old are each of the brothers?
• Guess and check.
s
• Work backwards.
pa
1.1
Buying and selling
pl
e
1.2
ge
• Test all possible combinations.
m
Need to Know
Sa
profit in $
% Profit = ------------------------ × 100%
CP
or
profit in $
------------------------ × 100%
SP
where CP = cost price, SP = selling price
To find the % Loss, substitute ‘Loss in $’ into the numerators of the above formulas.
× (100% + mark up)
Cost Price (CP)
Selling Price (SP)
÷ (100% + mark up)
For discounts:
× (100% − discount)
Marked Price (MP)
Sale Price (SP)
÷ (100% − discount)
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mathematics 9 essentials edition
AA Pearson Maths 9 EE-01.fm Page 9 Tuesday, April 24, 2012 10:46 AM
1.2
Worked Example 4
4
Calculate the sale price of a $46 shirt discounted by 25%.
Method 1: Find and subtract the discount
amount
Method 2: Find the remaining percentage
50% of $46 = 46 ÷ 2
= 23
Sale price = 75% of $46
= 0.75 × 46
= $34.50
25% of $46 = 23 ÷ 2
= $11.50
100% – 25% = 75%
s
Sale price = 46 − 11.50
= $34.50
ge
Worked Example 5
5
pa
A home theatre system costs an electrical store $510. It sells the system for $965.
Calculate, correct to one decimal place, the profit made as a percentage of:
(b) the selling price.
(a) Profit = SP – CP
= $(965 – 510)
= $455
Sa
m
profit
% Profit = ------------- × 100%
CP
455
= --------- × 100%
510
= 89.2% (1 d.p.)
pl
e
(a) the cost price
Worked Example 6
(b) Profit = $455
profit
% Profit = ------------- × 100%
SP
455
= ---------- × 100%
965
= 47.2% (1 d.p.)
6
A furniture store has a policy of selling their chairs and sofas with a mark up on the cost
price of 65%. What would a sofa that cost the store $300 be sold for?
65% + 100% = 165%
= 1.65
Selling price = 1.65 × $300
= $495
1 • Financial mathematics
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AA Pearson Maths 9 EE-01.fm Page 10 Tuesday, April 24, 2012 10:46 AM
1.2
Worked Example 7
7
A jewellery store has a policy of marking up the cost price of their goods by 75%. Calculate
the cost price of a necklace that was sold for $56.
100% + 75% = 175%
= 1.75
175% of CP = $56
1.75 × CP = $56
CP = $56 ÷ 1.75
= $32
8
ge
s
Worked Example 8
100% − 22.5% = 77.5%
= 0.775
pa
A smartphone has a sale price of $539 after a discount of 22.5% is applied. What was the
original marked price of the smartphone? Answer to the nearest dollar.
pl
e
77.5% of MP = $539
0.775 × MP = $539
.
1 2 Buying and selling
Sa
Answers
page 398
m
MP = $539 ÷ 0.775
= $695 (nearest $)
Fluency
4
5
1 Calculate the sale price of the following items:
(a) a $24 pair of shorts discounted by 15%
(b) a $95 pair of shoes discounted by 25%
(c) a $63.99 skirt discounted by 40%
(d) a $419.95 suit discounted by 37.5%.
2 (a) A camera costs a camera shop $360. The shop sells the camera for $504. Calculate,
correct to one decimal place, the profit as a percentage of:
(i) the cost price
(ii) the selling price.
(b) An old car costs a used car saleman $4200. He sells the car for $4050. Calculate, correct
to one decimal place, the loss as a percentage of:
(i) the cost price
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mathematics 9 essentials edition
(ii) the selling price.
AA Pearson Maths 9 EE-01.fm Page 11 Tuesday, April 24, 2012 10:46 AM
1.2
3 A clothing store has a policy of selling jeans and T-shirts with a mark up on the cost price
of 92%. Calculate the selling price of the following items, rounding your answer to the
nearest 5 cents:
(a) a pair of jeans, cost price $39.30
6
(b) a T-shirt, cost price $8.75.
4 A hardware store has a policy of marking up the cost price of their goods by 85%. Calculate
the cost price of the following items, rounding your answer to the nearest cent:
(a) a packet of nails, selling price $3.70
7
(b) a cordless drill, selling price $51.00.
5 (a) A tennis racquet has a sale price of $149 after a discount of 15% has been applied.
What was the original marked price of the racquet? Answer to the nearest dollar.
8
(b) A plasma TV has a sale price of $2497 after a discount of 7.5% has been applied. What
was the original marked price of the TV? Answer to the nearest dollar.
6 If a table cost $486 and was subsequently sold for $350, the percentage profit or loss, based
on the cost price, was:
( 486 – 350 )
---------------------------- × 100% loss
486
B
(---------------------------486 – 350 )
× 100% loss
350
C
(---------------------------486 – 350 )
× 100% profit
350
D
(---------------------------486 – 350 )
× 100% profit
486
ge
s
A
7 If a laptop is sold for $960 at a 114% profit, the cost of the laptop was:
$960 × 2.14 × 960
C
$960 × 1.14
B
$960 × 2.14
pa
A
D
$960
-----------2.14
8 If a desk is for sale for $140 after a 25% discount, it means that it was originally marked at:
$105
B
$175
Understanding
C
$186.67
pl
e
A
D
$245
cost price).
m
9 Calculate the selling price for the following cost prices and percentage profits (on
(a) CP = $48, percentage profit = 45%
(b) CP = $60, percentage profit = 60%
Sa
10 A builder buys $840 worth of timber to build an extension. If he is allowed a 12.5%
discount, how much does he pay?
11 A hairdresser gets a discount of 24% on hair products bought in bulk. How much is saved
on $370 worth of products?
12 A store purchases a bulk order of 120 watches for $960.
(a) Calculate the profit made if the watches are sold individually for $19.95 each.
(b) Calculate the total profit as a percentage of the cost price.
13 A store purchased a bulk order of pyjamas cheaply for a sale. If a customer paid $11 for
them at the sale, what were they marked at prior to the sale if they were reduced by 30%?
14 In Australia, a Goods and Services Tax (GST) of 10% is added to the price of all products
and services purchased by consumers (with the exception of some basic grocery items).
GST is added after the product has been marked up by the retailer. Mei is a clothing store
owner who has just purchased a large number of T-shirts for $6.49 each. She adds a mark
up of 180%, then the 10% GST.
(a) What is the final selling price of the T-shirts? (Answer to the nearest cent.)
(b) What amount of the final price is GST?
1 • Financial mathematics
11
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1.2
15 Most of the time the marked prices we see on goods in shops have the 10% GST already
added to the price. Find the original, pre-GST, price of:
(a) a DVD with a marked price of $29.90
(b) a vacuum cleaner with a marked price of $349.
16 A mechanic buys a car at an auction for $3120. The car is then repaired at a cost of $430.
It is resprayed and has its panels straightened for $840. The car is then advertised and sold
for $9800. Calculate the percentage profit on the selling price if the cost of advertising
was $80.
17 Louise bought shares in the following companies through a share broker (a person who
buys and sells shares on behalf of others). The share broker charges a fee of 2% of the
value of the shares bought and sold.
150 shares in Oro Mining, bought for $39.05 each
200 shares in Beacon Bank, bought for $19.86 each
250 shares in JeansEast, bought for $6.14 each
(a) Calculate the share broker’s fee.
s
(b) Including the fee, how much did Louise pay for her shares in total?
$42
$21.50
$8
pa
Oro Mining
Beacon Bank
JeansEast
ge
Louise instructs her share broker to sell her shares once they reach the following prices:
Her share broker does so and subtracts his fee.
(c) Calculate Louise’s profit from the sale of the shares.
(d) Calculate Louise’s profit as a percentage of the cost of her shares, including her share
Reasoning
pl
e
broker’s fee. State your answer correct to two decimal places.
18 Evie’s favourite shoe shop has a ‘buy one pair, get the second pair half-price’ offer.
Sa
m
Another shoe shop nearby is offering 20% off everything. If the regular retail price of the
shoes Evie wants in both stores is $49.95, which store is the cheaper place for Evie to buy
two pairs? How much would she save, compared with the other store?
19 A furniture store purchases a dining table and chairs for $750. It marks up this price
by 45% to obtain its selling price.
(a) What is the selling price of the dining set? State your answer correct to the nearest
dollar.
(b) The furniture is not selling, so the selling price is discounted by 45%. Calculate the sale
price to the nearest dollar.
(c) The mark up on the cost price was 45%. Why doesn’t a 45% discount on the selling
price return the price to the original cost price?
(d) What percentage saving will they be able to advertise if they take the price back to the
cost price? State your answer correct to the nearest whole number.
20 A stallholder at a market buys 20 kg of peanuts for $65, 5 kg of hazelnuts for $30 and
1 kg of cashews for $13. He mixes them together and puts them into plastic bags each
containing 200 g of mixed nuts and sells each bag for $1.00. If the plastic bags cost 2 cents
each, what is the percentage profit on the selling price of the nuts?
21 If you wanted to be able to advertise a discount of 30% on goods that cost you $5000 and
still make a profit of 10%, at what price would you initially advertise them? Give your
answer to the nearest dollar.
12
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mathematics 9 essentials edition
AA Pearson Maths 9 EE-01.fm Page 13 Tuesday, April 24, 2012 10:46 AM
1.2
Open-ended
22 (a) An outdoor furniture setting has a marked price of $999. State three different
percentage discounts, correct to one decimal place, that would make the selling price
between $750 and $800. Show your calculations.
(b) A lounge suite is sold for $2450. State three different percentage discounts, correct
to one decimal place, that could have been applied to the lounge suite if you know the
marked price was somewhere between $3000 and $3200. Also state the marked price
for your discount. Show the calculations that allow you to state your answer.
23 Using an example, explain why taking an additional 20% off an item already discounted
by 30% is not the same as one single overall discount of 50%.
Problem
Problem
oblem solving
ge
• Act it out.
• Draw a diagram.
• Break the problem into manageable parts.
pl
e
How much profit or loss does Patrick make?
Strategy options
pa
Patrick is an art lover who bought a
painting for $6000. A year later, Patrick
has some financial difficulties and has to
sell his painting for $7000. As soon as he
is able to, he buys the painting back
again. Unfortunately he has to pay
$8000 to get it back. A year later Patrick
moves house. He no longer has room for
the painting, so he sells it for $9000.
s
Patrick’s prized painting
1.2
1.3
Sa
m
Earning an income
Need to Know
An award is a document that sets out the minimum conditions of employment for
employees in a certain occupation or industry.
Wage requirements for employers
Employees must be paid at least the minimum rate in the award for their industry—it can
be more, but it can’t be less. Many awards have special conditions for junior employees
(those under 21 years of age).
Types of income
Wages:
Hourly rate of pay. Extra work may be paid as overtime at penalty rates
(time-and-a-half, double time).
Salary:
Weekly, monthly or annual rate of pay. Overtime not usually paid; time off
may be given instead.
Commission:
Retainer or flat fee plus percentage of the value of sales made, or a certain
amount for every sale.
Piece work:
Payment per item produced.
1 • Financial mathematics
13
AA Pearson Maths 9 EE-01.fm Page 14 Tuesday, April 24, 2012 10:46 AM
1.3
Worked Example 9
9
Sim is employed at a photographic studio. Sim’s job is covered by an award that states that
he must be paid a standard hourly rate of $15.80 for a standard 38-hour Monday to Friday
week. On Saturday he is paid time-and-a-half (1.5 times the standard hourly rate) for the
first 3 hours and double time (twice the standard rate) for any additional hours thereafter.
One particular week, Sim worked 4.5 hours on Saturday in addition to his standard hours.
How much money did he earn?
Total = $718.90
pa
Worked Example 10
ge
Standard hours: 38 × 15.8 = $600.40
Time-and-a-half: 3 × 15.8 × 1.5 = $71.10
Double time: 1.5 × 15.8 × 2 = $47.40
s
Standard hours: 38
Time-and-a-half: 3 hours
Double time: 1.5 hours
10
pl
e
Lina works as a real estate agent. She receives a retainer of $450 a fortnight, plus a
commission of 2.3% of the value of the property she sells. How much does Lina earn in a
fortnight in which she sells a house for $340 000?
m
C = 2.3% of $340 000
= 0.023 × 340 000
= $7820
Sa
Total income = 7820 + 450
= $8270
Worked Example 11
11
Emma is employed sewing dresses. She is paid at the rate of $7.50 per dress and she can
complete 42 dresses each week. Calculate her weekly income.
Income = 42 × 7.5
= $315
14
PEARSON
mathematics 9 essentials edition