Mathematics solution NCERT
Class 9 - Chapter 7: The mathematics of maybe: Introduction to Probability
Q1: Rank the following events on a scale from 0 (Impossible) to 1 (Certain).
(i) The next Monday will come after Sunday.
Ranking: 1
Label: Certain
Reason: The days of the week always follow the same order. Monday always comes after Sunday.
| Probability | Label |
|---|---|
| 1 | Certain |
(ii) It will snow in Mumbai in July.
Ranking: 0
Label: Impossible
Reason: Mumbai has a tropical coastal climate. July is the monsoon season, and snowfall does not occur there.
| Probability | Label |
|---|---|
| 0 | Impossible |
(iii) An elephant will walk through your classroom today.
Ranking: 0
Label: Impossible
Reason: Under normal circumstances, an elephant cannot enter a classroom. Therefore, the event is considered impossible.
| Probability | Label |
|---|---|
| 0 | Impossible |
(iv) You will greet at least one friend at school tomorrow.
Ranking: 0.8 (approximately)
Label: More Likely
Reason: Students usually meet and greet their friends at school. Although it is not guaranteed, it is very likely to happen.
| Probability | Label |
|---|---|
| 0.8 | More Likely |
Summary Table
| Event | Probability | Label |
|---|---|---|
| The next Monday will come after Sunday. | 1 | Certain |
| It will snow in Mumbai in July. | 0 | Impossible |
| An elephant will walk through your classroom today. | 0 | Impossible |
| You will greet at least one friend at school tomorrow. | 0.8 | More Likely |