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0580/32 May/Jun 2021, Question 4: Multiplication and Division of Fractions

Cambridge IGCSE Mathematics 0580 · Paper 32 (Core) · Calculator · 14 marks

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The question, in short

Work with fractions, decimals, percentages, rounding bounds, flour bags for cakes, and simultaneous equations for soup and biscuit costs.

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

Part (a) · 1 mark

Choose which of the five given fractions is equivalent to 7/12.

  1. 17/12 = (7 × 7)/(12 × 7) = 49/84

Answer49/84

Part (b) · 2 marks

Arrange 7/12, 0.6, 58%, 8/13 and 2/3 in ascending order.

  1. 17/12 = 0.583…, 0.6, 58% = 0.58, 8/13 = 0.615…, 2/3 = 0.666…
  2. 258% < 7/12 < 0.6 < 8/13 < 2/3

Answer58% < 7/12 < 0.6 < 8/13 < 2/3

Part (c) · 1 mark

Express 0.724 as a fraction in simplest form.

  1. 10.724 = 724/1000 = 181/250

Answer181/250

Part (d) · 2 marks

Given m = 415 g to the nearest 5 g, complete the lower and upper bounds for m.

  1. 1Half of 5 g is 2.5 g
  2. 2415 − 2.5 = 412.5 and 415 + 2.5 = 417.5
  3. 3412.5 ≤ m < 417.5

Answer412.5 ≤ m < 417.5

Part (e) · 3 marks

Find how many bags of flour are needed for 7 cakes when each cake uses three-quarters of a bag.

  1. 1Flour needed = 7 × 3/4 = 21/4 = 5 1/4 bags
  2. 2She must buy whole bags, so 6 bags

Answer6

Part (fi) · 1 mark

Complete the equation 3t + 2p = ... for 3 tins and 2 packets costing $15.50.

  1. 13t + 2p = 15.50

Answer15.50

Part (fii) · 1 mark

Write an equation for 5 tins of soup and 4 packets of biscuits costing $28.50.

  1. 15t + 4p = 28.50

Answer5t + 4p = 28.50

Part (fiii) · 3 marks

Solve the simultaneous equations 3t + 2p = 15.50 and 5t + 4p = 28.50, showing all working.

  1. 1Double the first equation: 6t + 4p = 31
  2. 2Subtract 5t + 4p = 28.5: t = 2.5
  3. 33 × 2.5 + 2p = 15.5, so 2p = 8
  4. 4t = 2.5, p = 4

Answert = 2.5, p = 4

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Also searched as: 0580/32/M/J/21 · 0580_s21_qp_32 · 0580 s21 32 · question 4.
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