Lemmara logoLemmaraWorked solution

4MA1/2H Jan 2020, Question 18: Histograms (Unequal Class Intervals)

Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 2H (Higher) · Calculator · 5 marks

اقرأ هذا الحل مشروحاً بالعربي ←

The question, in short

From a histogram of supermarket visit times in minutes, estimate a proportion of customers within a time range and a conditional probability for a randomly chosen customer.

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

Part (a) · 3 marks

Use the histogram bars to estimate the proportion of customers whose time in the supermarket was between 17 and 35 minutes.

  1. 1Frequency = frequency density × class width
  2. 2All bars: 7 + 17 + 9 + 15 + 72 = 120 customers
  3. 317 to 24: 1 × 7 = 7; 24 to 30: 15; 30 to 35: 4.8 × 5 = 24
  4. 4Between 17 and 35: 7 + 15 + 24 = 46
  5. 5Proportion = 46/120

Answer46/120

Part (b) · 2 marks

Given the chosen customer spent over 30 minutes, find the probability their time exceeded 36 minutes.

  1. 1Over 30 minutes is the 30−45 bar: width 15
  2. 2Over 36 minutes is 36 to 45: width 9 of the same bar
  3. 3Same frequency density, so P = 9/15

Answer9/15

Stuck on a step? Read the free lesson: Histograms (Unequal Class Intervals)

Practise more histograms (unequal class intervals) 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 histograms (unequal class intervals)

Also searched as: 4MA1 2H January 2020 · 4MA1/2H · 4ma1 jan20 2h · question 18.
Lemmara is an independent study tool, not affiliated with or endorsed by Pearson Edexcel. The worked solutions are Lemmara’s own.