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4MA1/1HR Jan 2020, Question 11: Upper and Lower Bounds

Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 1HR (Higher) · Calculator · 4 marks

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The question, in short

A cat weighs 4.3 kg to 2 significant figures; find its upper and lower bounds, then find the upper bound of G = e − f where e = 17 to nearest integer and f = 9.4 to 1 decimal place.

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

Part (a) · 1 mark

State the upper bound of the cat's weight, given 4.3 kg correct to 2 significant figures.

  1. 1The weight is 4.3 kg correct to 2 significant figures.
  2. 2The upper bound is halfway to the next possible value.
  3. 3So, upper bound = 4.35

Answer4.35

Part (b) · 1 mark

State the lower bound of the cat's weight, given 4.3 kg correct to 2 significant figures.

  1. 1The lower bound is halfway down to the previous possible value.
  2. 2So, lower bound = 4.25

Answer4.25

Part (c) · 2 marks

Using e = 17 to the nearest integer and f = 9.4 to one decimal place, calculate the upper bound of G = e − f.

  1. 1Upper bound of e = 17.5
  2. 2Lower bound of f = 9.35
  3. 3Largest G = largest e − smallest f
  4. 417.5 − 9.35 = 8.15

Answer8.15

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