---
title: "NCERT Solutions for Class 9 Maths Chapter 7 Exercise 7.3"
url: https://www.swavid.com/maths/class/9/chapter/the-mathematics-of-maybe-introduction-to-probability/ncert-solutions/exercise-7-3
dateModified: 2026-10-07T15:46:13+00:00
---

# NCERT Solutions for Class 9 Maths Chapter 7 Exercise 7.3

Chapter 7: The Mathematics of Maybe: Introduction to Probability. Every question from Exercise 7.3, with full working and the final answer.

Free PDF (20 pages): https://www.swavid.com/api/seo/pdf/ncert/maths/class-9/swavid-ncert-solutions-class-9-maths-chapter-7-the-mathematics-of-maybe-introduction-to-probability-1d9ff48bee.pdf

## Exercise Set 7.3

### Question 1

*3 marks · Short answer*

When a single 6-sided die is rolled, what is the total number of possible outcomes in the sample space?

**Solution**

1. The sample space for rolling a single 6-sided die consists of all the possible numbers that can appear on the top face.
2. The possible outcomes are $1, 2, 3, 4, 5, \text{ and } 6$.
3. Therefore, the total number of possible outcomes in the sample space is $6$.

**Answer:** 6

> Common mistake: Listing outcomes instead of giving the total number of outcomes.

### Question 2

*3 marks · Short answer*

For the following experiments write down the sample space S.
(i) Rolling a die and tossing a coin together.
(ii) Choosing a random integer between – 5 and + 5.
(iii) A box containing 5 green and 7 red balls. One ball is drawn at random.

**Part (i)**

1. Let H represent Heads and T represent Tails on the coin, and numbers $1$ to $6$ represent the die outcomes.
2. The sample space $S$ is the combination of each die outcome with both coin outcomes.
3. $S = \{(1, \text{H}), (1, \text{T}), (2, \text{H}), (2, \text{T}), (3, \text{H}), (3, \text{T}), (4, \text{H}), (4, \text{T}), (5, \text{H}), (5, \text{T}), (6, \text{H}), (6, \text{T})\}$

Answer (i): $S = \{(1, \text{H}), (1, \text{T}), (2, \text{H}), (2, \text{T}), (3, \text{H}), (3, \text{T}), (4, \text{H}), (4, \text{T}), (5, \text{H}), (5, \text{T}), (6, \text{H}), (6, \text{T})\}$

**Part (ii)**

1. An integer strictly between $-5$ and $+5$ excludes $-5$ and $+5$.
2. The integers between them are $-4, -3, -2, -1, 0, 1, 2, 3, 4$.
3. $S = \{-4, -3, -2, -1, 0, 1, 2, 3, 4\}$

Answer (ii): $S = \{-4, -3, -2, -1, 0, 1, 2, 3, 4\}$

**Part (iii)**

1. A box contains 5 green and 7 red balls, making 12 balls in total.
2. Let $G_1, G_2, G_3, G_4, G_5$ represent the green balls and $R_1, R_2, R_3, R_4, R_5, R_6, R_7$ represent the red balls.
3. The sample space is the set of all individual balls: $S = \{G_1, G_2, G_3, G_4, G_5, R_1, R_2, R_3, R_4, R_5, R_6, R_7\}$ (or simply representing them by colour type if indistinguishable: $\{ \text{Green}, \text{Red} \}$ depending on standard phrasing, but individual items are typically listed or grouped).

Answer (iii): $S = \{\text{Green}, \text{Red}\}$

**Answer:** Sample spaces for the given experiments are listed in the parts.

> Common mistake: Including $-5$ and $+5$ in the integer range or listing incorrect combinations.

### Question 3

*3 marks · Short answer*

In a village fair, there are 3 popular snacks available: Samosa, Pakora, and Bhaji. For drinks, villagers can choose either Chai or Lassi.
(i) List the sample space of all possible snack and drink combinations a person could choose at the fair.
(ii) List the event 'Selecting Samosa as a snack.'

**Part (i)**

1. There are 3 snacks (Samosa, Pakora, Bhaji) and 2 drinks (Chai, Lassi).
2. Each snack can be paired with each drink to form combinations.
3. $S = \{(\text{Samosa, Chai}), (\text{Samosa, Lassi}), (\text{Pakora, Chai}), (\text{Pakora, Lassi}), (\text{Bhaji, Chai}), (\text{Bhaji, Lassi})\}$

Answer (i): $S = \{(\text{Samosa, Chai}), (\text{Samosa, Lassi}), (\text{Pakora, Chai}), (\text{Pakora, Lassi}), (\text{Bhaji, Chai}), (\text{Bhaji, Lassi})\}$

**Part (ii)**

1. The event requires selecting Samosa as a snack with any of the available drinks.
2. The outcomes containing Samosa are (Samosa, Chai) and (Samosa, Lassi).
3. $E = \{(\text{Samosa, Chai}), (\text{Samosa, Lassi})\}$

Answer (ii): $E = \{(\text{Samosa, Chai}), (\text{Samosa, Lassi})\}$

**Answer:** Sample space and event are listed in the parts.

> Common mistake: Forgetting to pair each snack with both drinks.

## Related pages

- [All Chapter 7 NCERT solutions](https://www.swavid.com/maths/class/9/chapter/the-mathematics-of-maybe-introduction-to-probability/ncert-solutions)
- [Exercise 7.1](https://www.swavid.com/maths/class/9/chapter/the-mathematics-of-maybe-introduction-to-probability/ncert-solutions/exercise-7-1)
- [Exercise 7.2](https://www.swavid.com/maths/class/9/chapter/the-mathematics-of-maybe-introduction-to-probability/ncert-solutions/exercise-7-2)
- [Exercise 7.4](https://www.swavid.com/maths/class/9/chapter/the-mathematics-of-maybe-introduction-to-probability/ncert-solutions/exercise-7-4)

Solutions written by SwaVid, a personal AI tutor for Class 6 to 10 Maths and Science. Practise this chapter free: https://www.swavid.com/start/student