Connecting the Dots — Class 7 Mathematics NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 7 Mathematics chapter "Connecting the Dots" — 7 important questions with detailed answers for CBSE board exam preparation.
TL;DR: Free step-by-step NCERT solutions for Class 7 Mathematics chapter "Connecting the Dots" — 7 important questions with detailed answers for CBSE board e…
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Key Questions Covered:
- Define mean, median, and mode. Find all three for the data set: 3, 7, 5, 3, 9…
- A student scores: 80, 85, 78, 92, 88 in five tests. Calculate the mean and fi…
- Interpret a bar graph showing monthly rainfall: Jan-2, Feb-3, Mar-5, Apr-8, M…
- Define probability. A die is rolled. What is the probability of getting an ev…
- A bag contains 5 red balls, 3 blue balls, and 2 green balls. If one ball is d…
- Find the median and mode of the following marks: 45, 50, 55, 50, 60, 45, 55, …
- + 1 more questions in the full chapter
Solutions Summary:
| Question | Status |
|---|---|
| Define mean, median, and mode. Find all three for the dat… | ✓ Solved |
| A student scores: 80, 85, 78, 92, 88 in five tests. Calcu… | ✓ Solved |
| Interpret a bar graph showing monthly rainfall: Jan-2, Fe… | ✓ Solved |
| Define probability. A die is rolled. What is the probabil… | ✓ Solved |
| A bag contains 5 red balls, 3 blue balls, and 2 green bal… | ✓ Solved |
| Find the median and mode of the following marks: 45, 50, … | ✓ Solved |
Showing 6 of 7 questions
Q1: Define mean, median, and mode. Find all three for the data set: 3, 7, 5, 3, 9, 3, 5.
Definitions:
1. Mean (Average):
The mean is the sum of all values divided by the number of values.
Formula: Mean = (Sum of all values) / (Number of values)
2. Median:
The median is the middle value when data is arranged in order.
If the number of values is even, median is the average of two middle values.
3. Mode:
The mode is the value that appears most frequently (most often) in the data set.
A data set can have no mode, one mode, or multiple modes.
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For the data set: 3, 7, 5, 3, 9, 3, ...
Q2: A student scores: 80, 85, 78, 92, 88 in five tests. Calculate the mean and find how much above or below the mean each score is.
Given scores: 80, 85, 78, 92, 88
Step 1: Calculate the mean
Sum = 80 + 85 + 78 + 92 + 88 = 423
Number of scores = 5
Mean = 423 ÷ 5 = 84.6
Step 2: Find deviation from mean for each score
Deviation = Score - Mean
Score 1: 80 - 84.6 = -4.6 (below mean by 4.6)
Score 2: 85 - 84.6 = +0.4 (above mean by 0.4)
Score 3: 78 - 84.6 = -6.6 (below mean by 6.6)
Score 4: 92 - 84.6 = +7.4 (above mean by 7.4)
Score 5: 88 - 84.6 = +3.4 (above mean by 3.4)
Step 3: Summary table
| Score | Deviation from Mean | ...
Q3: Interpret a bar graph showing monthly rainfall: Jan-2, Feb-3, Mar-5, Apr-8, May-10, Jun-12 cm. Find the total and average rainfall.
Monthly Rainfall Data (in cm):
January: 2 cm
February: 3 cm
March: 5 cm
April: 8 cm
May: 10 cm
June: 12 cm
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Bar Graph Description:
The bar graph would show:
• X-axis: Months (Jan, Feb, Mar, Apr, May, Jun)
• Y-axis: Rainfall in cm (scale: 0 to 12 cm)
• Bar heights increasing from Jan (2) to Jun (12)
Visual pattern:
June has the highest rainfall (12 cm)
January has the lowest rainfall (2 cm)
Rainfall increases continuously from January to June
---
Calculating Total Rainfall:
Total = 2 + 3...
Q4: Define probability. A die is rolled. What is the probability of getting an even number?
Probability:
Probability is the chance or likelihood of an event occurring.
It is expressed as a ratio between 0 and 1, where:
0 = impossible event (will not happen)
1 = certain event (will definitely happen)
Formula: Probability = (Number of favorable outcomes) / (Total number of possible outcomes)
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Problem: A die is rolled. What is the probability of getting an even number?
Step 1: Identify all possible outcomes
When a die is rolled, the possible outcomes are: 1, 2, 3, 4, 5, 6
Total num...
Q5: A bag contains 5 red balls, 3 blue balls, and 2 green balls. If one ball is drawn at random, find the probability of drawing a red ball and a non-red ball.
Given:
Red balls: 5
Blue balls: 3
Green balls: 2
Step 1: Find total number of balls
Total = 5 + 3 + 2 = 10 balls
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Part 1: Probability of drawing a red ball
Step 2a: Identify favorable outcomes
Favorable outcomes (red balls) = 5
Step 3a: Calculate probability
P(red) = (Number of red balls) / (Total balls)
P(red) = 5/10 = 1/2 = 0.5
P(red) = 50%
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Part 2: Probability of drawing a non-red ball
Step 2b: Identify favorable outcomes
Non-red balls = Blue balls + Green balls
Non-red balls = ...
Q6: Find the median and mode of the following marks: 45, 50, 55, 50, 60, 45, 55, 50, 65.
Given marks: 45, 50, 55, 50, 60, 45, 55, 50, 65
Step 1: Arrange marks in ascending order
45, 45, 50, 50, 50, 55, 55, 60, 65
Number of values = 9 (odd number)
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Finding the Median:
Step 2: Find the middle position
For odd number of values: Median position = (n + 1)/2
Median position = (9 + 1)/2 = 10/2 = 5th position
Step 3: Identify the median
Counting from the ordered list:
1st: 45, 2nd: 45, 3rd: 50, 4th: 50, 5th: 50, ...
Median = 50
---
Finding the Mode:
Step 4: Count frequency of ea...
Showing 6 of 7 questions. Visit the full page for complete solutions.
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