Racing Seconds

Note: The exact time is shown on a clock image that cannot be viewed here. Based on the context of the chapter, Raghav started practising Yoga at 06:00 a.m. (This answer should be read from the clock shown in the figure in your textbook.)

Note: The exact time is shown on a clock image that cannot be viewed here. Based on the context of the chapter, Raghav finished practising Yoga at 06:45 a.m. (This answer should be read from the clock shown in the figure in your textbook.)

Given: Start time = 06:00 a.m., End time = 06:45 a.m.

Time spent = End time − Start time
$$= 06:45 - 06:00 = 45 \text{ minutes}$$

Raghav spent 45 minutes practising Yoga.

Given: Start time = 01:15 p.m., End time = 01:42 p.m.

Both times are in the same hour (1 p.m.), so we subtract the minutes:
$$42 - 15 = 27 \text{ minutes}$$

Time elapsed = 27 minutes.

Given: Start time = 03:18 p.m., End time = 08:18 p.m.

The minutes are the same (18 minutes) in both times, so we only count the hours:
$$8 - 3 = 5 \text{ hours}$$

Time elapsed = 5 hours.

Given: Start time = 09:15 a.m., End time = 11:30 a.m.

Step 1: From 09:15 a.m. to 11:15 a.m. = 2 hours
Step 2: From 11:15 a.m. to 11:30 a.m. = 15 minutes

Total time elapsed = 2 hours + 15 minutes

Time elapsed = 2 hours 15 minutes.

Given times:
- Raghav = 1 hour 20 minutes = 80 minutes
- Rani = 2 hours 10 minutes = 130 minutes
- Ritu = 1 hour 35 minutes = 95 minutes

Comparing: 130 > 95 > 80

Rani took the longest time (2 hours 10 minutes).

Given times:
- Raghav = 1 hour 20 minutes = 80 minutes
- Rani = 2 hours 10 minutes = 130 minutes
- Ritu = 1 hour 35 minutes = 95 minutes

Comparing: 80 < 95 < 130

Raghav took the least time (1 hour 20 minutes).

Rules used:
- For a.m. times: 12-hour and 24-hour formats are the same (for times after midnight up to 12:59 a.m., add 12 for 12 a.m.; otherwise same digits).
- For p.m. times (except 12 p.m.): Add 12 to the hour in 12-hour format to get 24-hour format.

Row 1: 05:30 a.m. → 05:30 hours ✓ (already given)

Row 2: 08:35 hours → Since 08:35 is before noon, it is 08:35 a.m.

Row 3: 11:55 a.m. → 11:55 is before noon, so 24-hour = 11:55 hours

Row 4: 02:30 p.m. → 14:30 hours ✓ (already given)

Row 5: 05:30 p.m. → $5 + 12 = 17$, so 17:30 hours

Row 6: 09:35 p.m. → $9 + 12 = 21$, so 21:35 hours

Completed table:
| 12-hour format | 24-hour format |
|---|---|
| 05:30 a.m. | 05:30 hours |
| 08:35 a.m. | 08:35 hours |
| 11:55 a.m. | 11:55 hours |
| 02:30 p.m. | 14:30 hours |
| 05:30 p.m. | 17:30 hours |
| 09:35 p.m. | 21:35 hours |

Converting each 12-hour time to 24-hour format:

1. 06:30 a.m. → 06:30 hours ✓ matches 06:30 hours
2. 08:45 p.m. → $8 + 12 = 20$, so 20:45 hours ✓ matches 20:45 hours
3. 11:45 p.m. → $11 + 12 = 23$, so 23:45 hours ✓ matches 23:45 hours
4. 04:30 a.m. → 04:30 hours ✓ matches 04:30 hours
5. 07:30 p.m. → $7 + 12 = 19$, so 19:30 hours ✓ matches 19:30 hours
6. 01:30 a.m. → 01:30 hours ✓ matches 01:30 hours

Correct Matches:
- 06:30 a.m. ↔ 06:30 hours
- 08:45 p.m. ↔ 20:45 hours
- 11:45 p.m. ↔ 23:45 hours
- 04:30 a.m. ↔ 04:30 hours
- 07:30 p.m. ↔ 19:30 hours
- 01:30 a.m. ↔ 01:30 hours

We use the fact that 1 minute = 60 seconds. Activities that are very quick (done in less than 60 seconds) are measured in seconds; activities that take longer are measured in minutes.

| Activity | Seconds | Minutes |
|---|---|---|
| Blinking of eyes | ✓ | |
| Switching on and switching off the lights | ✓ | |
| Counting from 1–20 | ✓ | |
| Filling a glass from the tap | ✓ | |
| Melting of an ice-cube | | ✓ |
| Making a phone call | | ✓ |
| Sitting down on the floor | ✓ | |
| Drinking a glass of water | ✓ | |
| Snapping fingers | ✓ | |
| Washing hands | ✓ | |

(Note: Some answers like 'filling a glass' or 'washing hands' may vary; the above are suggested answers. Discuss with your teacher.)

This is an activity-based question.

Method: Use a stopwatch or count seconds (one-one-thousand, two-one-thousand…). Start skipping and count how many times you skip in 10 seconds.

Example answer: A child can typically skip the rope about 10 to 20 times in 10 seconds. (Your actual number will vary — record your own result.)

This is an activity-based question.

Method: Start a stopwatch, write the word FRIEND, and stop the watch.

Example answer: It typically takes about 5 to 10 seconds to write the word FRIEND. (Record your own result.)

This is an activity-based question.

Method: Mark a 100 m distance. Start a stopwatch when you begin running and stop it when you cross the finish line.

Example answer: A Class 5 student typically takes about 25 to 40 seconds to run 100 m. (Record your own result.)

Note: The answer depends on the two clock images showing start and end positions of the seconds hand.

Method: Count the number of seconds between the position of the seconds hand on the first clock and the second clock.

Example: If the seconds hand moved from the 12 to the 9 (i.e., 45 seconds), then Rani took 45 seconds to get out of her bed. (Read the exact value from your textbook clocks.)

Note: The answer depends on the two clock images.

Method: Find the difference in the positions of the seconds hands on both clocks.

Example: If the seconds hand moved from 12 to 6 (i.e., 30 seconds), then Raghav took 30 seconds. (Read the exact value from your textbook clocks.)

Note: The answer depends on the two clock images.

Method: Find the difference in the positions of the seconds hands on both clocks.

Example: If the seconds hand moved from 12 to 3 (i.e., 15 seconds), then Ritu took 15 seconds. (Read the exact value from your textbook clocks.)