Class 8 Mathematics Chapter 5: Tales by Dots and Lines — practice questions with answers
Free practice for Class 8 Mathematics, Chapter 5: Tales by Dots and Lines. Try the solved questions below, then take a free test with instant marking and explanations.
42 questions12 easy, 20 medium, 10 hardNCERT · CBSE · State boards
Sample questions with solutions
Q1. A new value greater than the mean is included. What happens to the mean?
- It increases
- It decreases
- It stays the same
- It becomes zero
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Answer: A. It increases
Why: The balance shifts towards the new value. [p.105]
Why: The balance shifts towards the new value. [p.105]
Q2. The mean of a data set is 20. If 10 is added to every value, what is the new mean?
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Answer: 30 (± 0)
Why: Adding a constant to every value adds it to the mean. [p.107]
Why: Adding a constant to every value adds it to the mean. [p.107]
Q3. The mean of a data set is 12. If every value is multiplied by 5, what is the new mean?
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Answer: 60 (± 0)
Why: (5x₁ + … + 5xₙ)/n = 5a. [p.108]
Why: (5x₁ + … + 5xₙ)/n = 5a. [p.108]
Q4. Using the family-size frequency table (sizes 3–10 with frequencies 3, 11, 9, 7, 3, 1, 1, 1), what is the total number of students?
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Answer: 36 (± 0)
Why: 3 + 11 + 9 + 7 + 3 + 1 + 1 + 1 = 36. [p.110]
Why: 3 + 11 + 9 + 7 + 3 + 1 + 1 + 1 = 36. [p.110]
Q5. Which tool helps a teacher quickly find totals and averages for many students’ marks?
- A spreadsheet
- A ruler
- A compass
- A protractor
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Answer: A. A spreadsheet
Why: Formulas compute totals and averages instantly. [p.112]
Why: Formulas compute totals and averages instantly. [p.112]
Q6. A line graph is generally used to show ______.
- change over time
- parts of a whole
- a single value
- a map
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Answer: A. change over time
Why: e.g. monthly maximum temperatures. [p.117]
Why: e.g. monthly maximum temperatures. [p.117]
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Frequently asked questions
How many practice questions are there for Class 8 Mathematics Chapter 5: Tales by Dots and Lines?
42 questions (12 easy, 20 medium, 10 hard). A few are solved on this page; the free test shows the answer and explanation for every question after you submit.
Is this chapter from the NCERT book?
Yes — it follows the NCERT Class 8 Mathematics syllabus, used by CBSE and many state boards.