NCERT Solutions for Class 9 Maths Chapter 10 — Exercise Set 10.5#
In a 100% stacked bar chart, every bar has the same length (100%), and each piece shows a share of the total. It is good for comparing proportions, but it hides the totals.
1. The smart watch data of 5 people was tracked from Monday to Friday. The recorded data tells us how many hours each person spent lying down, sitting, and standing or moving around, etc. #
| Lying down | Sitting | Standing or moving around | |
|---|---|---|---|
| Pavani (Patient) | 20 | 3 | 1 |
| Raghu (Nurse) | 7 | 4 | 13 |
| Zakir (Teacher) | 8 | 6 | 10 |
| Sahana (Student) | |||
| Julie (______) | 8 | 10 | 6 |
(i) How much time does Sahana spend per day in each of these body-states? Make a reasonable guess and fill her row in the table.
Answers will vary. The three numbers must add up to 24 hours. A school student sleeps about 8–9 hours, sits in class and while studying for many hours, and moves about at school, at play and doing chores. A reasonable guess:
| Lying down | Sitting | Standing or moving around | |
|---|---|---|---|
| Sahana (Student) | 9 | 8 | 7 |
(ii) Guess what activity or work Julie could be engaged in based on the data.
Julie sits for 10 hours a day — the most of anyone — and moves about for 6 hours. She probably has a desk job, such as an office worker, software engineer, accountant, bank clerk or driver. (Other guesses that fit the data are fine.)
(iii) Complete the chart below based on the tabular data.
Each person’s hours are divided by 24 to get the shares. For example, Sahana: lying down $\dfrac{9}{24} = 37.5\%$, sitting $\dfrac{8}{24} \approx 33.3\%$, moving $\dfrac{7}{24} \approx 29.2\%$.