Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
1. There are 112 balls in a bag. If 84 of them are yellow and the rest are blue, what percentage of the
balls are blue?
A. 25%
B. 28%
C. 75%
□
D. 84%
(1 mark)
2. There are 14 boys in S1B, which makes up 40% of all students in this class. How many students
are there in S1B?
A. 21
B. 35
C. 56
□
D. 60
(1 mark)
3. Among 80 MP3 files stored in a smartphone, 35% of them are pop music and there are 32 piano
solos. If the rest of the MP3 files are guitar solos, what percentage of the files are guitar solos?
A. 13%
B. 20%
C. 25%
□
D. 33%
(1 mark)
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1
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
4. Find the following unknowns.
(a) a % of 75 is 18.
(1 mark)
(b) 25% of 112 is b.
(1 mark)
(c) 24% of c is 30.
(1 mark)
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2
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
5. There are 900 students in a school, where 55% are boys. 40% of the boys and 60% of the girls
have reading habits. What percentage of students have reading habits?
(4 marks)
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3
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
6. The ticket prices of a stand-up comedy show are $120, $180 and $250. 60% of the tickets are
$120-tickets, 30% of the tickets are $180-tickets, and there are 800 $250-tickets. If all of the
tickets are sold, find the income obtained.
(5 marks)
END OF PAPER
 2015 Chung Tai Educational Press. All rights reserved.
4
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
1. Benjamin obtained 50 Halloween candies last year and he obtained 80 this year. What is the
percentage increase in the number of Halloween candies obtained?
A. 30%
B. 37.5%
C. 60%
□
D. 62.5%
(1 mark)
2. Which of the following is the greatest?
A. Increase from 90 by 20%.
B. Increase from 100 by 6.
C. Decrease from 110 by 5.
□
D. Decrease from 120 by 15%.
(1 mark)
3. In a group of students, there are 275 boys, which makes up 55% of all students. If the number of
boys increases by 8% and the number of girls decreases by 72, then the total number of students
A. decreases by 10%.
1
B. decreases by 11 % .
9
C. increases by 10%.
1
D. increases by 11 % .
9
□
(1 mark)
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5
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
4. The weight of Scott was 60 kg last year. If his weight increases by 5% this year, find his weight
this year.
(2 marks)
5. The length of a square decreases from 4 cm to 2 cm. Find the percentage decrease in the area of the
square.
(2 marks)
6. After increasing A by 10%, it is equal to B. If B decreases by 10%, is it equal to A? Explain your
answer.
(2 marks)
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6
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
7. The number of red envelopes sold in February was 30% more than that in January. The number
of red envelopes sold in March was 80% less than that in February. It is given that 3 445 red
envelopes were sold in February.
(a) How many red envelopes were sold in January?
(2 marks)
(b) How many red envelopes were sold in March?
(2 marks)
(c) What was the percentage increase / decrease in the number of red envelopes sold from January
to March?
(2 marks)
Solution:
(a)
(b)
 2015 Chung Tai Educational Press. All rights reserved.
7
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
(c)
END OF PAPER
 2015 Chung Tai Educational Press. All rights reserved.
8
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
1. Amy bought a book for $120. She sold it to Betty at a profit of 20%. Betty then sold the book to
Coey and lost $30. How much did Coey pay for the book?
A. $100.8
B. $108
C. $110
□
D. $114
(1 mark)
2. Dave sells a watch for $1 725 at a loss of 8%. Find the cost of the watch.
A. $1 587
B. $1 597
C. $1 863
□
D. $1 875
(1 mark)
3. Which of the following cases will give a profit of more than $9?
I.
Cost  $50, percentage profit  18%
II. Cost  $100, selling price  $110
III. Selling price  $92, percentage profit  15%
A. II only
B. III only
C. II and III only
□
D. I, II and III
(1 mark)
 2015 Chung Tai Educational Press. All rights reserved.
9
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
4. Jimmy bought 2 dozens of energy bars for $96. If he sold all the energy bars for $5 each, find the
percentage profit.
(2 marks)
5. A sports shop sold a soccer for $88 at a loss of 20%, and a badminton racket for $206 at a profit of
$16.
(a) Find the cost of the soccer.
(2 marks)
(b) Find the cost of the badminton racket.
(1 mark)
(c) Did the shop make an overall profit or loss for selling these two items? Explain your answer.
(2 marks)
(d) Find the overall percentage profit / loss for selling these two items.
(2 marks)
Solution:
(a)
(b)
(c)
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 10 
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
(d)
6. A cafe owner sold two items as follows.
Item
Cost
Selling price
Percentage profit
A lemon tart
$20
$22
10%
A cup of green tea
$10
$11
10%
The owner claims that an overall profit of 20% is made from selling a lemon tart and a cup of
green tea. Do you agree? Explain your answer.
(3 marks)
END OF PAPER
 2015 Chung Tai Educational Press. All rights reserved.
 11 
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
1. The marked price of a suit is $888. If it is sold at a discount of 25% on its marked price, find the
selling price of the suit.
A. $222
B. $444
C. $666
□
D. $1 110
(1 mark)
2. A battery charger is $39 cheaper if it is sold at a discount of 12%. Find the marked price of the
battery charger.
A. $44
B. $286
C. $325
□
D. $364
(1 mark)
3. Which of the following gives the least percentage discount?
A. Marked price  $120, selling price  $114
B. Marked price  $125, discount  $10
C. Selling price  $117, discount  $13
□
D. 7% off
(1 mark)
 2015 Chung Tai Educational Press. All rights reserved.
 12 
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
4. The original marked price of a headset is $x. The shop owner raises the marked price by 12% and
then sells it at a discount of 5% on the new marked price. If the headset is sold for $266, find x.
A. 222
B. 250
C. 273
□
D. 283
(1 mark)
5. Vanessa buys a soft toy for $129 with a marked price of $150. Find the percentage discount.
(2 marks)
6. Jayden buys a cap for $23 at a discount of 8% on its marked price.
(a) Find the marked price of the cap.
(b) Find the discount.
(2 marks)
(1 mark)
Solution:
(a)
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 13 
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
(b)
7. A department store is holding a seasonal sale and all items are sold at a discount of 10%. If the
total purchase after discount exceeds $1 000, an extra discount of 5% will be offered.
(a) Miss Yam is going to buy an item with a marked price of $800. How much should she pay?
(2 marks)
(b) If Miss Yam decides to buy an additional item with a marked price of $400, how much more
should she pay?
(4 marks)
Solution:
(a)
(b)
END OF PAPER
 2015 Chung Tai Educational Press. All rights reserved.
 14 
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
Stage Quiz  § 6.1
1. Number of blue balls  112  84
 28
28
 100%
112
 25%
 Required percentage 
 The answer is A.
1A
(1)
2. Let n be the number of students in S1B.
n  40%  14
n  14  40%
 35
 There are 35 students in S1B.
 The answer is B.
1A
(1)
32
 100%
80
 40%
3. Percentage of the files which are piano solos 
 Percentage of the files which are guitar solos  100%  35%  40%
 25%
 The answer is C.
1A
(1)
4. (a) 75  a %  18
18
a
 100
75
 24
1A
(1)
(b) 112  25%  b
b  28
1A
(1)
(c) c  24%  30
c  30  24%
 125
1A
(1)
 2015 Chung Tai Educational Press. All rights reserved.
 15 
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
5. Number of boys  900 55%
 495
Number of girls  900  495
 405
Number of boys with reading habits  495 40%
 198
1A
Number of girls with reading habits  405 60%
 243
1A
 Percentage of students with reading habits 
1M
198  243
 100%
900
441

 100%
900
 49%
1A
(4)
6. Percentage of the tickets which are $250-tickets  100%  60%  30%
 10%
Let n be the total number of tickets.
n  10%  800
n  800  10%
 8 000
 There are 8 000 tickets in total.
1A
Number of the $120-tickets  8 000  60%
 4 800
1A
Number of the $180-tickets  8 000  30%
 2 400
1A
 Income obtained  $(4 800  120  2 400  180  800  250)
 $(576 000  432 000  200 000)
 $1 208 000
1M
1A
(5)
Stage Quiz  § 6.2
1. Increase in number  80  50
 30
30
 100%
 Percentage increase 
50
 60%
 The answer is C.
1A
(1)
 2015 Chung Tai Educational Press. All rights reserved.
 16 
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
2. A. 90  (1  20%)  90  1.2
 108
B. 100  6  106
C. 110  5  105
D. 120  (1  15%)  120  0.85
 102
 The answer is A.
1A
(1)
3. Let n be the original number of students in the group.
n  55%  275
n  275  55%
 500
New number of boys  275  (1  8%)
 2751.08
 297
New number of girls  (500  275)  72
 153
New total number of students  297  153
 450
Decrease in the total number of students  500  450
 50
50
 100%
 Percentage decrease 
500
 10%
 The answer is A.
1A
(1)
4. Increase in weight  60  5% kg
 3 kg
1A
 His weight this year  (60  3) kg
 63 kg
1A
(2)
Alternative method:
His weight this year  60  (1  5%) kg
 60  1.05 kg
1M
 63 kg
1A
(2)
 2015 Chung Tai Educational Press. All rights reserved.
 17 
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
5. Decrease in the area  (42  22 ) cm 2
 (16  4) cm2
 12 cm 2
1A
12
 100%
16
 75%
 Percentage decrease 
1A
(2)
6. A(1  10%)  B
If B decreases by 10%,
B(1  10%)  A(1  10%)(1  10%)
 A(1.1)(0.9)
 0.99 A
1A
A
 It is not equal to A.
1A
(2)
7. (a) Let x be the number of red envelopes sold in January.
x(1  30%)  3 445
1M
x  3 445  (1  30%)
 3 445  1.3
 2 650
 The number of red envelopes sold in January was 2 650.
1A
(2)
(b) Number of red envelopes sold in March
 3 445  (1  80%)
 3 445  0.2
 689
1M
1A
(2)
(c) Decrease in the number of red envelopes sold from January to March
 2 650  689
 1 961
1A
 Percentage decrease 
1 961
 100%
2 650
 74%
1A
(2)
 2015 Chung Tai Educational Press. All rights reserved.
 18 
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
Stage Quiz  § 6.3
1. Amount paid by Betty  $120  (1  20%)
 $120 1.2
 $144
Amount paid by Coey  $144  $30
 $114
 The answer is D.
1A
(1)
2. Let $C be the cost of the watch.
C (1  8%)  1 725
C  1 725  (1  8%)
 1 725  0.92
 1 875
 The cost of the watch is $1 875.
 The answer is D.
1A
(1)
3. I.
Profit  $50  18%
 $9
II. Profit  $110  $100
 $10
III. Cost  $92  (1  15%)
 $92 1.15
 $80
 Profit  $92  $80
 $12
 The answer is C.
1A
(1)
4. Number of energy bars  2  12
 24
Selling price of 24 energy bars  $5  24
 $120
Profit  $120  $96
 $24
24
 100%
 Percentage profit 
96
 25%
1A
1A
(2)
 2015 Chung Tai Educational Press. All rights reserved.
 19 
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
5. (a) Let $C be the cost of the soccer.
C (1  20%)  88
1M
C  88  (1  20%)
 88  0.8
 110
 The cost of the soccer is $110.
1A
(2)
(b) Cost of the badminton racket  $206  $16
 $190
1A
(1)
(c) Total amount obtained from selling the two items  $88  $206
 $294
Total cost of the two items  $110  $190
 $300
 $294
 A loss is made.
1M
1A
(2)
(d) Loss  $300  $294
 $6
1A
6
 100%
 Overall percentage loss 
300
 2%
1A
(2)
6. Total cost  $20  $10
 $30
Total selling price  $22  $11
 $33
Overall profit  $33  $30
 $3
1A
3
 100%
30
 10%
 20%
 Overall percentage profit 
1A
 The claim is disagreed.
1A
(3)
 2015 Chung Tai Educational Press. All rights reserved.
 20 
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
Stage Quiz  § 6.4
1. Discount  $888  25%
 $222
Selling price  $888  $222
 $666
 The answer is C.
1A
(1)
2. Let $m be the marked price of the battery charger.
m  12%  39
m  39  12%
 325
 The marked price of the battery charger is $325.
 The answer is C.
1A
(1)
3. A. Discount  $120  $114
 $6
6
 100%
120
 5%
Percentage discount 
10
 100%
125
 8%
B. Percentage discount 
C. Marked price  $117  $13
 $130
13
 100%
Percentage discount 
130
 10%
D. Percentage discount  7%
 The answer is A.
1A
(1)
4. x(1  12%)(1  5%)  266
x  266  (1  12%)  (1  5%)
 266  1.12  0.95
 250
 The answer is B.
1A
(1)
 2015 Chung Tai Educational Press. All rights reserved.
 21 
Chapter 6
Effective Learning Mathematics Stage Quiz | S1A
5. Discount  $150  $129
 $21
1A
21
 100%
 Percentage discount 
150
 14%
1A
(2)
6. (a) Let $m be the marked price of the cap.
m(1  8%)  23
1M
m  23  (1  8%)
 23  0.92
 25
 The marked price of the cap is $25.
1A
(2)
(b) Discount  $25  $23
 $2
1A
(1)
7. (a) Required amount  $800  (1  10%)
1M
 $800  0.9
 $720
1A
(2)
(b) Overall marked price  $800  $400
 $1 200
1A
Amount to be paid after 10% off  $1 200  (1  10%)
 $1 200  0.9
 $1 080
 $1 000
1A
 Miss Yam can enjoy the extra discount of 5%.
Amount to be paid after 5% off  $1 080  (1  5%)
 $1 080  0.95
 $1 026
 Extra amount should be paid  $1 026  $720
 $306
1A
1A
(4)
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 22 