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0580/31 May/Jun 2025, Question 22: Compound Interest

Cambridge IGCSE Mathematics 0580 · Paper 31 (Core) · Calculator · 6 marks

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The question, in short

Three money problems: simplify an investment ratio, find a shared total from a ratio and a difference, and calculate compound interest over 5 years.

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

Part (a) · 1 mark

Write the ratio of Anil's $2000 to Baz's $7500 in simplest form.

  1. 12000 : 7500
  2. 2Divide both by 500
  3. 34 : 15

Answer4 : 15

Part (b) · 2 marks

Kamil and Lavik share money in ratio 5 : 9, Lavik gets $72 more; find the total shared.

  1. 1Difference = 9 − 5 = 4 parts = $72
  2. 21 part = 72 ÷ 4 = $18
  3. 3Total = 14 parts = 14 × 18 = $252

Answer252

Part (c) · 3 marks

Find the total interest on $4000 invested for 5 years at 3.5% per year compound interest.

  1. 1Amount = 4000 × 1.035⁵
  2. 2= 4750.74…
  3. 3Interest = 4750.74… − 4000 = 750.74…
  4. 4$751

Answer751 or 750.7…

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