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0580/33 Oct/Nov 2023, Question 1: Compound Interest

Cambridge IGCSE Mathematics 0580 · Paper 33 (Core) · Calculator · 12 marks

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The question, in short

Work through a restaurant bill, fractions and percentages, compound interest, and a dollars-to-Swiss-francs conversion graph, finding missing values and explaining a graph method.

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

Part (ai) · 2 marks

Find the missing soup price so the listed items add to the total of $25.40.

  1. 113.30 + 4.80 + 3.81 = 21.91
  2. 2Soup = 25.40 − 21.91 = $3.49

Answer3.49

Part (aii) · 1 mark

Express the drinks cost of $3.81 as a percentage of the $25.40 total.

  1. 13.81/25.40 × 100 = 15%

Answer15

Part (bi) · 1 mark

Calculate 2/5 of $2400.

  1. 12400 ÷ 5 = 480
  2. 22/5 of $2400 = 480 × 2 = $960

Answer960

Part (bii) · 2 marks

Reduce $3450 by 18%.

  1. 118% of 3450 = 0.18 × 3450 = 621
  2. 23450 − 621 = $2829 (or 3450 × 0.82 = 2829)

Answer2829

Part (c) · 3 marks

Find the value after 5 years of $14000 invested at 1.6% yearly compound interest, to the nearest dollar.

  1. 1Value = 14000 × (1 + 1.6/100)⁵
  2. 2= 14000 × 1.016⁵ = 15156.4…
  3. 3≈ $15156 to the nearest dollar

Answer15156

Part (dia) · 1 mark

Use the conversion graph to convert $80 into Swiss francs.

  1. 1Go up from $80 on the Dollars axis to the line, then across to the Swiss francs axis
  2. 2$80 = 72 Swiss francs

Answer72

Part (dib) · 1 mark

Use the conversion graph to convert 108 Swiss francs into dollars.

  1. 1Go across from 108 on the Swiss francs axis to the line, then down to the Dollars axis
  2. 2108 Swiss francs = $120

Answer120

Part (dii) · 1 mark

Describe how the graph can be used to convert $360, which is beyond its scale.

  1. 1$360 is off the graph, so split it into values on the graph: 360 = 200 + 160
  2. 2From the graph, $200 = 180 francs and $160 = 144 francs
  3. 3Add: $360 = 180 + 144 = 324 Swiss francs

AnswerCorrect explanation, using any correct combination of values between 0 and 200 to reach 360

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Also searched as: 0580/33/O/N/23 · 0580_w23_qp_33 · 0580 w23 33 · question 1.
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