Ratio, proportion and percentages
Ratio, proportion and percentages

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Ratio, proportion and percentages

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.)

MU120_4M3

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