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4024/21 May/Jun 2023, Question 2: Percentage Increases and Decreases

Cambridge O Level Mathematics 4024 · Paper 21 (Calculator) · Calculator · 8 marks

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The question, in short

Work through time, pay rate, percentage change and simple interest problems: find a finish time, an hourly rate, a reduced working time, a percentage increase, and an initial investment.

Summarised in our own words. Use the official paper for the exact wording and any diagrams.

Part (a) · 1 mark

Starting at 10.45 am, add 2 hours 50 minutes to find the finishing time on Monday.

  1. 110 45 + 2 hours = 12 45
  2. 212 45 + 50 minutes = 1 35 pm (13 35)

Answer1.35 pm or 13 35

Part (bi) · 1 mark

Xavier works 5 days of 4 1/2 hours each and earns $261 weekly; calculate his hourly pay rate.

  1. 1Hours per week = 5 × 4.5 = 22.5
  2. 2Rate = 261 ÷ 22.5 = $11.60 per hour

Answer11.60

Part (bii) · 2 marks

Xavier's working time drops by 20%; find the new duration in hours and minutes.

  1. 14.5 − 20/100 × 4.5 = 4.5 − 0.9 = 3.6 hours
  2. 20.6 hours = 0.6 × 60 = 36 minutes
  3. 33 hours 36 minutes

Answer3 hours 36 minutes

Part (c) · 2 marks

Miguel's income rises from $32 000 to $33 408; calculate the percentage increase.

  1. 1Increase = 33 408 − 32 000 = 1408
  2. 21408/32 000 × 100 = 4.4%

Answer4.4

Part (d) · 2 marks

With simple interest at 1.2% per year for 3 years giving $890.96, find the initial amount x.

  1. 1x + x × 1.2/100 × 3 = 890.96
  2. 21.036x = 890.96
  3. 3x = 890.96 ÷ 1.036 = 860.00

Answer860.00

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Also searched as: 4024/21/M/J/23 · 4024_s23_qp_21 · 4024 s23 21 · question 2.
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