Lemmara logoLemmaraWorked solution

4MA1/2HR Jan 2019, Question 17: Upper and Lower Bounds

Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 2HR (Higher) · Calculator · 4 marks

اقرأ هذا الحل مشروحاً بالعربي ←

The question, in short

Using numbers given to 2 or 3 significant figures, find bounds for P = ef and Q = t/w, showing working and rounding the results as specified.

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

Part (a) · 2 marks

Find the lower bound of P = ef using e = 4.8 and f = 0.26, each to 2 significant figures; show working and give the answer to 3 significant figures.

  1. 1Lower bound of e = 4.75, lower bound of f = 0.255
  2. 2Lower bound of P = 4.75 × 0.255 = 1.21125
  3. 3Correct to 3 s.f.: 1.21

Answer1.21

Part (b) · 2 marks

Find the upper bound of Q = t/w using t = 2.73 to 3 significant figures and w = 0.04 to 1 significant figure; show working and give the answer to 2 significant figures.

  1. 1Upper bound of Q = upper t ÷ lower w
  2. 2Upper t = 2.735, lower w = 0.035
  3. 32.735 ÷ 0.035 = 78.14…
  4. 4Correct to 2 s.f.: 78

Answer78

Stuck on a step? Read the free lesson: Upper and Lower Bounds

Practise more upper and lower bounds questions

Real 4MA1 past-paper questions, marked on your working like the exam, with a worked solution for every part.

Practise free on Lemmara

More past-paper questions on upper and lower bounds

Also searched as: 4MA1 2HR January 2019 · 4MA1/2HR · 4ma1 jan19 2hr · question 17.
Lemmara is an independent study tool, not affiliated with or endorsed by Pearson Edexcel. The worked solutions are Lemmara’s own.