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0580/43 Oct/Nov 2022, Question 1: Direct Proportion in Real Life

Cambridge IGCSE Mathematics 0580 · Paper 43 (Extended) · Calculator · 14 marks

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The question, in short

Use a recipe's ingredient masses for 12 servings to find a percentage, scale to 18 people, and work out servings from limited milk and other ingredients.

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

Part (ai) · 1 mark

Express 280 g cheese as a percentage of 460 g mushrooms.

  1. 1280/460 × 100 = 60.86… ≈ 60.9%

Answer60.9 or 60.86 to 60.87

Part (aii) · 2 marks

Scale 250 g butter from 12 servings to 18 servings.

  1. 1Butter = 250/12 × 18
  2. 2= 375 g

Answer375

Part (aiii) · 3 marks

With 2.2 litres milk and 1.5 kg of each other ingredient, find the largest number of people served.

  1. 1Milk: 2200 ÷ 800 × 12 = 33 people
  2. 2Pasta: 1500 ÷ 600 × 12 = 30 people
  3. 3Other ingredients allow more (butter 72, cheese 64, mushrooms 39)
  4. 4Greatest number = 30

Answer30

Part (bi) · 2 marks

Given $2.40 in 2019 is a 25% rise, find the 2018 cost.

  1. 1A 25% increase means: 2018 cost × 1.25 = 2.40
  2. 22018 cost = 2.40 ÷ 1.25 = 1.92

Answer1.92

Part (bii) · 3 marks

After a further 15% rise in 2020, find the overall percentage increase from 2018 to 2020.

  1. 1Multiplier = 1.25 × 1.15 = 1.4375
  2. 2Increase = (1.4375 − 1) × 100
  3. 3= 43.75%

Answer43.75 or 43 3/4

Part (c) · 3 marks

Packets 11.5 cm wide (nearest 0.5 cm) on a 2 m shelf (nearest 0.1 m): find the maximum number fitting, showing working.

  1. 1Shelf upper bound = 2.05 m = 205 cm
  2. 2Packet lower bound = 11.5 − 0.25 = 11.25 cm
  3. 3205 ÷ 11.25 = 18.2…
  4. 4Maximum number = 18

Answer18

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Also searched as: 0580/43/O/N/22 · 0580_w22_qp_43 · 0580 w22 43 · question 1.
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