3.1.1 Try some yourself
Activity 17
Express each of the following percentages as fractions:
(a) 40%
(b) 8%
(c) 70%
(d)
Answer
(a) 40%=
(b) 8%=
(c) 70%=
(d)
Activity 18
Express each of the following percentages as decimals:
(a) 50%
(b) 85%
(c) 7%
(d)
Answer
(a) 50% =
= 0.5(b) 85% =
=0.85(c) 7% =
= 0.07(d)
Activity 19
A survey was carried out on 840 couples to investigate family income. 75% of the women were in paid work; 90% of the men were in paid work; 18% of the couples had a joint income of less than £160 per week.
(a) How many women were in paid work?
(b) How many men were in paid work?
(c) How many couples had a joint income of less than £160 per week?
Answer
(a) 75% of 840 = 0.75 × 840 = 630,
so 630 women were in paid work.
(b) 90% of 840 = 0.9 × 840 = 756,
so 756 men were in paid work.
(c) 18% of 840 = 0.18 × 840 = 151.2.
But 151.2 is not a whole number. So 151 couples had a joint income of less than £160 per week. (The survey result must have been rounded, as a percentage, to the nearest whole number.)