1A percentage

Express the following percentage as fraction (in simplest form) and as decimals.

a)45%

b)7.5%

c) 0.5%

d)5 whole 1/2%

Answer explanation

a)45%~ percentage

45%=45/100 ~ fraction

= 9/20

45%=45/100~ decimal

=45÷100

=0.45

b)7.5%~ percentage

7.5%=7.5/100 ~ fraction

= 75/1000

=3/40

7.5%=7.5/100~ decimal

=7.5÷100

= 0.075

c) 0.5%~ percentage

0.5%=0.5/100 ~ fraction

= 5/1000

=1/200

0.5%=0.5/100~ decimal

=0.5÷100

= 0.005

d)5 whole 1/2%~ percentage

5 whole 1/2%=5 whole 1/2/100 ~ fraction = 5.5/100

= 55/1000

=11/200

5 whole 1/2 %=5 whole 1/2 /100~ decimal

=5 whole 1/2÷100

= 5.5/100

=5.5÷100

=0.055

Express each of the following as a percentage

a)1/2

b)3/4

c) 0.32

d)0.08

Answer explanation

a)1/2=1/2×100

=50%

b)3/4= 3/4×100

=75%

c) 0.32= 0.32×100

= 32%

d)0.08= 0.08× 100

= 8%

In worked example 3, if Wai Fun spent 1/3 of her salary on food and 1/6 of her salary on transport instead, what should the answers to parts (a) and (b) be ?

Answer explanation

a) 1/3 + 1/6 = 1/2

1/2×100=50

b) 100-50=50

Express the following percentage as fractions (in simplest form) and as decimals.

a) 125%

b) 112.5%

c) 100.8%

d) 300%

Answer explanation

a) 125%~ percentage

125% =125/100~ fraction

=5/4

125%= 125/100~ decimal

=125÷100

= 1.25

b) 112.5%~ percentage

112.5% =112.5/100~ fraction

=1125/1000

= 9/8

112.5%= 112.5/100~ decimal

=112.5÷100

= 1.125

c) 100.8%~ percentage

100.8% =100.8/100~ fraction

=1008/1000

= 126/125

100.8%= 100.8/100~ decimal

=100.8÷100

= 1.008

d) 300%~ percentage

300% =300/100~ fraction

=3

300%= 300/100~ decimal

=300÷100

= 3

Express each of the following as a percentage.

a) 7/2

b) 1 whole 1/5

c) 1.56

d)1.17

e)6

Answer explanation

a) 7/2 = 7/2 ×100

= 350%

b) 1 whole 1/5 = 1 whole 1/5 ×100

= 120%

c) 1.56 = 1.56×100

= 156%

d)1.17= 1.17×100

= 117%

e)6 = 6×100

= 600%

Find the following.

a) 40% of $60

b) 75% of 93kg

Answer explanation

a) 40% of $60 = 40/100 ×60

= $24

b) 75% of 93kg = 75/100 × 93

= 69.75kg

Express the following.

Give ur answers to 3 significant figure where necessary.

a) 8mm as a percentage of 1.5cm

b) 400ml as a percentage of 2.4l

C) 20s as a percentage of 1.5 min

Answer explanation

a) 1.5×10= 15

8/15 ×100=53.3%

b) 2.4l × 1000= 2400

400/2400 ×100= 16.7%

c) 1.5×60= 90

20/90× 100 = 22.2%

In worked example 8,if Hong Kim scored 10 marks out of 15 for a maths test and 12 marks out of 20 for a Science test instead, Which subject did he do better in?

Answer explanation

Maths: 10/15 ×100= 66.66

= 66.7

Science: 12/20×100= 60

Khai Mun also pays $8 less for a pair of slippers after a 25% discount.

What is the usual price of the pair of slippers?

Answer explanation

25% - $8 (÷25)

1% - 8÷25 (×100)

= 0.32

100% - 0.32×100

= $32

A chair costs $32.30 after a 15% discount. Find the original cost of the chair.

Answer explanation

85%- $32.30(÷85)

1% - 32.30÷85 (×100)

=0.38

100% - 0.38×100

= $38