Percentage - Practice 1 (Qn 1-20)

Below are the key answers for the questions. (More difficult ones will be explained in details)

Concept : To convert decimal or fraction to percentage, we multiply the decimal or fraction by 100%)

Please show your workings instead of the final answer.

(Note : The fraction in this answer key are typed using /. Write one number on top of the other in your working. )



Question 1

a) 2/25
b) 1/4
c) 1/2
d) 33/55
e) 1/20
f) 3/20
g) 11/25
h) 39/50

Question 2

a) 0.09
b) o.9
c) 0.15
d) 0.62
e) 3% = 3/100 = 0.03
f) 0.35
g) 0.40
h) 0.86

Question 3

a) 75%
b) 80%
c) 7/8 = 7/8 x 100% = 87.5%
d) 70%
f) 84%
g) 48%
h) 30/75 = 30/75 x 100% = 40%
i) 60/150 = 60/150 x 100% = 40%
j) 180/600 = 180/600 x 100% = 30%


Question 4

a) 0.1 = 0.1 x 100% = 10%
b) 0.01 = 0.01 x 100% = 1%
c) 0.9 = 0.9 x 100% = 90%
d) 8%
e) 75%
f) 0.001 = 0.001 x 100% = 0.1%
g) 0.045 = 0.045 x 100% = 4.5%
h) 0.245 = 0.245 x 100% = 24.5%

Question 5

a) 11.25
b) 702
c) $75
d) 180m
e) 10.5 l
f) 9.6 kg

Question 6

100% - 85% = 15%


Question 7

100% - 45% - 20% = 35%

Question 8

36 / 400 x 100 % = 9%

Question 9

No. passed = 200 - 7 = 193

% passed = 193/200 x 100% = 96.5%


Question 10

% having computers = 320/500 x 100% = 64%


Question 11

a) % of the pupils walk to school = 28/40 x 100% = 70%

b) % of the pupils go to school by bus = 100% - 70% = 30%


Question 12

2/5 = 2/5 x 100% = 40%


Question 13

Amount of money = spent + left

spent 2/5 ---> left 3/5

% of his money left = 3/5 x 100% = 60%


Question 14

% of his stamps that are Malaysia stamps
= 3/5 x 100%
= 60%

Question 15

Total = Singapore stamps + Malaysia stamps

Malaysia stamps => 1 - 3/4 = 1/4 of the total stamps

1/4 = 1/4 x 100% = 25%


Question 16

To find percentage, we express the answer as a fraction first.

Fraction of the cloth used = 75cm / 3m (make the units the same)

= 75 cm / 300 cm

= 1/4

% of the cloth used = 1/4 x 100% = 25%

Question 17

Gold medals = 45 - 22 - 14 = 9

% of the medals that are gold medal = 9/45 x 100% = 20%
Question 18