The distances travelled, to the nearest kilometre, by 120 commuters are summarised in the table below.
| Distance (km) | 1–5 | 6–10 | 11–20 | 21–40 |
|---|---|---|---|---|
| Frequency | 18 | 30 | 42 | 30 |
Estimate the number of these commuters who travelled less than 15 km.
Explain why your answer to part (a) is only an estimate.
8 exam-style questions on AQA A Level Maths 2.2.1 Single-variable data diagrams. Each one has a worked solution and a mark scheme showing where the marks go.