NCERT Solutions for Class 5 Maths Mela Chapter 12 Racing Seconds

Page 155

Raghav practices yoga in the morning.

Let us find out

1. At what time did Raghav start practising Yoga? ……………….
Answer:
Raghav starts practising Yoga at 5:35 A.M.

2. At what time did he finish? …………….
Answer:
Raghav finish practising Yoga at 5:55 A.M.

3. How much time did he spend practising Yoga? ………………..
Answer:
Yoga start time = 5:35 A.M.
Yoga finish time = 5:55 A.M.
Time spend on practising yoga = 5:55 A.M. – 5:35 A.M. = 20 minutes

4. Find the time elapsed between the given time periods. Share your strategies.
(a) 01:15 p.m. to 01:42 p.m.?
(b) 03:18 p.m. to 08:18 p.m.?
(c) 09:15 a.m. to 11:30 a.m.?
Answer:
a) Start Time = 1:15 p.m.
End time = 1:42 p.m.
Elapsed time = End time – Start time
= 1:42 – 1:15
= 27 minutes

b) Start Time = 3:18 p.m.
End time = 8:18 p.m.
Elapsed time = End time – Start time
= 8:18 – 3:18
= 5 hours

c) Start Time = 9:15 a.m.
End time = 11:30 p.m.
Elapsed time = End time – Start time
= 11:30 – 9:15
= 2 hours 15 minutes

5. The table below shows the time taken by 3 children to paint a picture.

(a) Who took the longest time?
(b) Who took the least time?
Answer:
(a) Rani took longest time 2 hours 10 minutes
(b) Raghav took least time 1 hour 20 minutes

6. Fill in the blanks by writing the time in the appropriate format.

Answer:

7. Match the following.

Answer:

Page 156

School Race

In situations like a race, ‘seconds’ help us observe small differences in time taken by participants. Each participant took 1 minute but how much more?

Answer:
First place took 55 seconds more than 1 minute
Second place took 56 seconds more than 1 minute
Third place took 57 seconds more than 1 minute

Identify the child who won the race. How much time did the child take?
Answer:
Winner: The child in the red shirt won the race, standing at the number 1 position on the victory podium.
Time Taken: The winning child took 1 minute and 55 seconds to complete the race.

Page 157

Let Us Do

Estimate whether you would take seconds or minutes to complete the following activities. Tick the appropriate cell.

Answer:

Page 158

List events other than the ones listed above that you can do or that can happen in less than a minute or in a few seconds.

Answer:
Tying shoelaces: minutes
Brushing your teeth: minutes
Opening a door: seconds
Turning on a fan: seconds
Clapping your hands: seconds
Chewing a bite of food: minutes

Estimate and verify how many of these you can do in a minute.

Answer:

Page 158

Let Us Find

1. Find out the number of times you can skip the rope in 10 seconds.
Answer:
I am good at skipping, I can around 8-10 skips in 10 seconds.

2. How long does it take you to write the word FRIEND?
Answer:
It takes 3 seconds if I write fast.

3. How long does it take you to run 100 m?
Answer:
I take about 20 seconds, but when I tried to run, it takes 18 seconds only.

Page 159

Let Us Do

Observe the clocks and fill in the blanks.

Answer:

Page 160

Draw the missing seconds hand on the clocks on the right side.

Answer:

Page 161

Let Us Do

1. Use the double number line below to complete the conversions.
(a)

Answer:

(b) Do as instructed. You can use the above double number line for the following conversions.
1 hours 10 minutes = _____ minutes
2 hours 45 minutes = _____ minutes
3 hours 15 minutes = _____ minutes
4 hours 20 minutes = _____ minutes
75 minutes = ____ hour ____ minutes
150 minutes = ____ hours ____ minutes
220 minutes = ____ hours ____ minutes
390 minutes = ____ hours ____ minutes
Answer:
1 hours 10 minutes = 70 minutes
2 hours 45 minutes = 165 minutes
3 hours 15 minutes = 195 minutes
4 hours 20 minutes = 260 minutes
75 minutes = 1 hour 15 minutes
150 minutes = 2 hours 30 minutes
120 minutes = 2 hour
150 minutes = 2 hour 30 minutes
220 minutes = 3 hours 40 minutes
390 minutes = 6 hours 30 minutes

(c) Fill in the blanks in the double number line to complete the conversions.

Answer:

2. Raghav studies Mathematics, English, Hindi, and The World Around us subjects. He took 50 minutes to study each of the subjects. Find the total time taken in hours and minutes. Share your strategies with your class.
Answer:
He took 50 minutes to study each subjects
Total subject = 4 (Mathematics, English, Hindi, The World Around Us)
Total time to study all subject = 50 × 4
= 200 minutes
We know that 1 hour = 60 minutes
Therefore, 200 minutes = 200 ÷ 60 hours
= 3 hours and 20 minutes

3. Raghu left his house at 08:00 hours and arrived at his Nana ji’s house at 09:05 hours. How long did he take to reach his house?
Answer:
Start time: 08:00 AM
Arrival time: 09:05 AM
Difference = 09:05 – 08:00 = 1 hour 5 minutes.
So, he took 1 hour 5 minutes to reach his house.

4. Jyoti went to play at 06:15 PM. She came back after 1 hour 45 minutes. At what time did she reach home?
Answer:
Start time: 06:15 PM Add 1 hour and 45 minutes.
1 hour after 06:15 PM = 07:15 PM.
Now, adding 45 more minutes to 07:15 PM, we get it is 08:00 PM.
So, Jyoti reached home at 08:00 PM

5. Ragini took 1 hour 10 minutes to do her homework. She finished it at 09:40 PM. What time did she start?
Answer:
Finish time: 09:40 PM
Subtract 1 hour and 10 minutes from 09:40 PM.
Subtracting 1 hour from 09:40 PM gives 08:40 PM.
Now, subtracting 10 minutes from 08:40 PM, we get 08:30 PM.
So, Ragini started her homework at 08:30 PM.

6. A group of children left for a picnic at 08:30 AM. They returned after 4 hours and 10 minutes. At what time did they return?
Answer:
Start time: 08:30 AM.
We have to add 4 hours and 10 minutes.
4 hours after 08:30 AM gives 12:30 PM.
Now, adding 10 more minutes to 12:30 PM, we get 12:40 PM.
So, the children returned at 12:40 PM.

7. Raji started her homework at 06:00 PM. She finished her homework in 1 hour 30 minutes. At what time did she finish?
Answer:
Start time: 06:00 PM.
We have to add 1 hour and 30 minutes.
1 hour after 06:00 PM gives 07:00 PM.
Now, adding 30 more minutes to 07:00 PM, we get 07:30 PM.
So, Raji finished her homework at 07:30 PM.

8. Alya goes out to play at 05:30 PM and comes back after 1 hour 10 minutes. At what time does she come back?
Answer:
Start time: 05:30 PM.
We have to add 1 hour and 10 minutes.
1 hour after 05:30 PM gives 06:30 PM.
Now, adding 10 more minutes to 06:30 PM, we get 06:40 PM.
So, Alya comes back at 06:40 PM.

9. If the lunch break of a school starts at 12:30 PM and ends in 35 minutes, what time will lunch end?
Answer:
Start time: 12:30 PM.
We have to add 35 minutes.
30 minutes after 12:30 PM gives 01:00 PM.
Now, adding 5 more minutes to 01:00 PM, we get 01:05 PM.
So, the lunch break will end at 01:05 PM.

10. It is 08:35 PM right now. What time will it be after 8 hours and 25 minutes?
Answer:
Start time: 08:35 PM.
We have to add 8 hours and 25 minutes.
8 hours after 08:35 PM gives 04:35 AM.
Now, adding 25 more minutes to 04:35 AM, we get 05:00 AM.
So, the time will be 05:00 AM after 8 hours and 25 minutes.