Practicing with Maths Mela Class 5 Solutions Chapter 12 Racing Seconds Question Answer NCERT Solutions improves a student’s confidence in the subject.
Class 5 Maths Chapter 12 Racing Seconds Question Answer Solutions
Racing Seconds Class 5 Maths Solutions
Class 5 Maths Chapter 12 Solutions
Let Us Find Out (NCERT Pg 155-156)
Question 1.
Raghav practices yoga in the morning.
(i) At what time did Raghav start practising Yoga?
(ii) At what time did he finish? _______.
(iii) How much time did he spend practising Yoga?
Answer:
(i) The first clock face in the image shows the hour hand pointing in between 5 and 6 and the minute hand point at 7, indicating 5 : 35. So, the Raghav started practising Yoga at 5:35 am.
(ii) The second clock face in the image shows the hour hand pointing in between 5 and 6 and the minute hand point at 11, indicating 5 : 55. So, Raghav finished practising Yoga at 5 : 55 am.
(iii) Ravhav started Yoga at 5 : 35 and finished at 5 : 55.
∴ Duration of Yoga = 5 : 55 – 5 : 35 = 20 min
Hence, the time spent by Raghav in practising Yoga is 20 minutes.
Question 2.
Find the time elapsed between the given time periods. Share your strategies.
(i) 01 : 15 pm to 01 : 42 pm?
(ii) 03 : 18 pm to 08 : 18 pm?
(iii) 09 : 15 am to 11 : 30 am?
Answer:
(i) We have, 01 : 15 pm and 01 : 42 pm.
So, elapsed time = 01 : 42 pm-01 : 15 pm = 27 minutes
(ii) We have, 03 : 18 pm and 08 : 18 pm.
So, elapsed time = 08 : 18 pm-03 : 18 pm = 05 hours
(iii) We have, 09 : 15 am and 11 : 30 am.
So, elapsed time = 11 : 30 am – 09 : 15 am = 2 hours 15 minutes
Question 3.
The table below shows the time taken by 3 children to paint a picture.
(i) Who took the longest time?
(ii) Who took the least time?
Answer:
Given, the time taken by Raghav
= 1 hour 20 minutes
= 1 × 60 minutes + 20 minutes
[∵ 1 hour = 60 minutes]
= 80 minutes
The time taken by Rani
= 2 hour 10 minutes
= 2 × 60 minutes + 10 minutes
= 120 minutes + 10 minutes
[∵ 1 hour = 60 minutes]
= 130 minutes
and the time taken by Ritu
= 1 hour 35 minutes
= 1 × 60 minutes + 35 minutes
[∵ 1 hour = 60 minutes]
= 95 minutes
(i) The longest time is 130 minutes, which is taken by Rani.
(ii) The least time is 80 minutes, which is taken by Raghav.
Question 4.
Fill in the blanks by writing the time in the appropriate format.
Answer:
(ii) We have, 08:35 hours
Since, the hours are less than 12, so it will be 8:35 am.
(iii) We have, 11:55 am.
Since, it is am, the hours remain the same.
So, answer is 11:55 hours.
(v) We have, 05:30 pm.
Since, it is pm, add 12 to the hours
(5 + 12 = 17)
So, answer is 17:30 pm.
(vi) We have, 09:35 pm.
Since, it is pm, add 12 to the hours
(09 + 12 = 21)
So, answer is 21 : 35 pm.
Question 5.
Match the following.
Answer:
(i) (c) We have, 06 : 30 am.
Since, it’s am, the hours remain the same.
So, answer is 06 : 30 hours.
(ii) (d) We have, 08 : 45 pm.
Since, it’s pm, add 12 to the hours
(08 + 12 = 20)
So, answer is 20 : 45 hours.
(iii) (b) We have, 11 : 45 hours.
Since, it’s pm, add 12 to the hours (11 + 12 = 23)
So, aniswer is 23 : 45 hours.
(iv) (e) We have, 04:30 am.
Since, it’s am, the hours remain the same.
So, answer is 04 : 30 hours.
(v) (f) We have, 07 : 30 pm.
Since, it’s pm, add 12 to the hours (07 + 12 = 19)
So, answer is 19 : 30 hours.
(vi) (a) We have, 01 : 30 am.
Since, it’s am, the hours remain the same.
So, answer is 01:30 hours.
School Race (NCERT Pg 156-157)
Question 6.
Akira, Sunita and Mary are participating in a 200m walking race.
Do you notice the use of a new unit ‘seconds’ in the picture?
1 minute = 60 seconds
In situations like a race, ‘seconds’ help us observe small differences in time taken by participants.
(i) Each participant took 1 minute but how much more?
(ii) Identify the child who won the race. How much time did the child take?
Answer:
(i) Given, the time taken by Ist position holder = 01 : 55
= 1 minutes 55 seconds
So, Ist position holder took 55 seconds more than 1 minute.
Time taken by IInd position holder = 01: 56
= 1 minute 56 seconds
So, IInd position holder took 56 seconds more than 1 minute.
Time taken by IIIrd position holder = 01 : 57
= 1 minute 57 seconds
So, IIIrd position holder took 57 seconds more than 1 minute.
(ii) Clearly, Ist position holder won the race because she took the least time, i.e. 1 minute and 55 seconds to complete the race.
Let Us Do (NCERT Pg 157-158)
Question 7.
Estimate whether you would take seconds or minutes to complete the following activities. Tick the appropriate cell.
(ii) 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:
(i) (a) Blinking of eyes – Seconds
(b) Switching on and switching of the lights – Seconds
(c) Counting from 1 to 20 – Seconds
(d) Filling a glass from the tap – Seconds
(e) Melting of an ice-cube – Minutes
(f) Making a phone call-Seconds
(g) Sitting down on the floor -Seconds
(h) Drinking a glass of water-Minutes
(i) Snapping fingers = Seconds
(j) Washing hands = Minutes
(ii) Taking a deep breath
Clapping your hands
Catching a ball
Saying “hello”.
Question 8.
Estimate and verify how many of these you can do in a minute.
Answer:
Do yourself.
Let Us Find (NCERT Pg 158)
Question 9.
(i) Find out the number of times you can skip the rope in 10 seconds.
(ii) How long does it take you to write the word FRIEND?
(iii) How long does it take you to run 100 m ?
Answer:
Do yourself.
Let Us Do (NCERT Pg 159-160)
Question 10.
Observe the clocks and fill in the blanks.
Answer:
(i) In both the figures, the hour and minute hands are at the same position and the second hand is shifted from 12 to 6, i.e. 30 seconds.
So, Rani took 30 seconds to get out of her bed.
(ii) In both the figures, the hour and minute hands are at the same position and the second hand is shifted from 12 to 7, i.e. 35 seconds.
So, Raghav took 35 seconds to move from his room to the kitchen.
(iii) In both the figures, the hour and minute hands are at the same position and the second hand is shifted from 9 to 12, i.e. 15 seconds.
So, Ritu took 15 seconds to pick up a piece of paper from the floor.
(iv) In both the figures, the hour hand and second hand are at the same position and the minute hand is shifted by 1 minute i.e. 60 seconds.
So, Raghu took 60 seconds to wash his spoon and plate.
Question 11.
Draw the missing seconds hand on the clocks on the right side.
Answer:
(i) The first clock shows the second hand at 12. After 20 seconds, the second hand will move 20 markings clockwise from 12. Therefore, the second hand on the second clock should be drawn pointing to the 4.
(ii) The first clock shows the second hand at 12. After 30 seconds, the second hand will move 30 markings clockwise from 12.
Therefore, the second hand on the second clock should be drawn pointing to the 6.
(iii) ∵ 60 seconds = 1 minute
This signifies a full minute is passed and the second hand completes a full circle.
So, the second hand on the second clock should be drawn pointing to the 9 while the minute hand should be drawn pointing to the just next marking after 6 in clockwise direction.
(iv) The first clóck shows the second hand at 11.
After 40 seconds, the second hand will move 40 marking clockwise from 11.
Therefore, the second hand on the second clock should be drawn pointing to the 7.
Let Us Do (NCERT Pg 161-163)
Question 12.
Use the double number line below to complete the conversions.
(i)
(ii) Do as instructed. You can use the above double number line for the following conversions.
Answer:
(i) 1 hour × 2 = 2 hours
4 hours = 4 × 60 minutes = 240 minutes [∵ 1 hour = 60 minutes ]
7 hours = 7 × 60 min= 420 minutes [∵ 1 hour = 60 minutes]
480 minutes = \(\frac{480}{60}\) hour = 8 hours
[∵ 1 minute = \(\frac{1}{60}\) hour ]
9 hours = 9 × 60 minutes = 540 minutes [ ∵ 1 hour = 60 minutes]
660 minutes = \([latex]\frac{660}{60}\) hour = 11 hours
[∵ 1 minute = \([latex]\frac{1}{60}\) hour]
720 minutes = \(\frac{720}{60}\) hour = 12 hours
[∵ 1 minute = \(\frac{1}{60}\) hour]
(ii) (a) We have, 1 hour 10 minutes
= 1 × 60 minutes + 10 minutes
[∵ 1 hour = 60 minutes]
= 70 minutes
(b) We have, 2 hours 45 minutes
= 2 × 60 minutes + 45 minutes
[∵ 1 hour = 60 minutes]
= 120 minutes + 45 minutes
= 165 minutes
(c) We have, 3 hours 15 minutes
= 3 × 60 minutes + 15 minutes
[∵ 1 hour = 60 minutes]
= 180 minutes + 15 minutes
= 195 minutes
(d) We have, 4 hours 20 minutes
= 4 × 60 minutes + 20 minutes
[∵ 1 hour = 60 minutes]
= 240 minutes + 20 minutes
= 260 minutes
(e) We have, 75 minutes
= 60 minutes + 15 minutes
= 1 hour15 minutes
[∵ 60 minutes = 1 hour]
(f) We have, 150 minutes
= 120 minutes + 30 minutes
= 2 × 60 minutes + 30 minutes
= 2 hours 30 minutes
[∵ 60 minutes = 1 hour]
(g) We have, 220 minutes
= 180 minutes + 40 minutes
= 3 × 60 minutes +40 minutes
= 3 hours 40 minutes
[∵ 60 minutes = 1 hour]
(h) We have, 390 minutes
= 360 minutes + 30 minutes
= 6 × 60 minutes + 30 minutes
= 6 hours 30 minutes
[∵ 60 minutes = 1 hour]
Question 13.
(i) Fill in the blanks in the double number line to complete the conversions
Answer:
(i) 60 seconds × 5 = 300 seconds
10 minutes = 10 × 60 seconds = 600 seconds [ ∵ 1 minutes = 60 seconds]
15 minutes = 15 × 60 seconds = 900 seconds [∵ 1 minutes = 60 seconds ]
1200 seconds = \(\frac{1200}{60}\) minutes
= 20 minutes
[∵ 1 sec = \(\frac{1}{60}\) minute ]
1500 seconds = \(\frac{1500}{60}\) minutes
= 25 minutes
[∵ 1 second = \(\frac{1}{60}\) minute]
(ii) (a) We have, 320 sec = 300 sec + 20 sec
= 5 × 60 sec+20 sec
= 5 min 20 sec
[∵ 60 sec = 1 min]
(b) We have, 225 sec = 180 sec+45 sec
= 3 × 60 sec+45 sec
= 3 min 45 sec
[∵ 60 sec = 1 min]
(c) We have, 700 sec = 660 sec + 40 sec
= 11 × 60 sec + 40 sec
= 11 min 40 sec
[∵ 60 sec = 1 min]
(d) We have, 1000 sec = 960 sec+40 sec
= 16 × 60 sec + 40 sec
= 16 min 40 sec
[∵ 60 sec = 1 min]
(e) We have, 10 min 13 sec
= 10 × 60 sec + 13 sec
[∵ 1 min = 60 sec]
= 600 sec+13 sec
= 613 sec
(f) We have, 4 min 8 sec = 4 × 60 sec + 8 sec
[∵ 1 min = 60 sec]
= 240 sec + 8 sec
= 248 sec
(g) We have, 15 min 40 sec
= 15 × 60 sec + 40 sec
[∵ 1 min = 60 sec]
= 900 sec + 40 sec
= 940 sec
Question 14.
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:
Given, Raghav studies 4 subject Mathematics, English, Hindi and The World Around Us and the time taken by him to study each subject = 50 minutes.
So, the total time taken by him to study all subject = 50 minutes × 4
= 200 minutes
= 180 minutes +20 minutes
= 3 × 60 minutes + 20 minutes
= 3 hours 20 minutes
[ ∵ 60 minutes = 1 hour]
Question 15.
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:
Given, the time at which Raghu left his house = 08:00 hours
and the time at which he arrived at his Nanaji’s house = 09 : 05.
So, the time taken by Raghu to reach his house = 09:05 hours – 08:00 hours
= 1 hour and 5 minutes
Question 16.
Jyoti went to play at 06:15 PM. She came back after 1 hour 45 minutes. At what time did she reach home?
Answer:
Given, the time at which Jyoti went to play
= 06 : 15 PM
and the time duration of playing
= 1 hour 45 minutes
= 1 : 45
So, the time at which she reached home
= 06 : 15 + 1 : 45
= 07: 60
= 08: 00 [∵ 60 minutes = 1 hour]
Hence, Jyoti reached home at 08:00 PM.
Question 17.
Ragini took 1 hour 10 minutes to do her homework. She finished it at 09:40 PM. What time did she start?
Answer:
Given, the time at which she finished her homework = 09:40 PM and the time duration of doing homework
= 1 hour 10 minutes
= 1 : 10
So, the starting time of home work
= 09 : 40 – 1 : 10
= 08 : 30
Hence, Ragini started her homework at 08:30 PM.
Question 18.
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:
Given, the time at which the children left
for the picnic = 08 : 30 AM
and the duration = 4 hours 10 minutes
= 4 : 10
So, the time at which they returned
= 08 : 30 + 04 : 10
= 12 : 40
So, the children returned at 12 : 40 PM.
Question 19.
Raji started her homework at 06:00 PM. She finished her homework in 1 hour 30 minutes. At what time did she finish?
Answer:
Given, the time at which Raji started her homework = 06:00 PM and duration of doing homework
= 1 hour 30 minutes
= 1 : 30
So, the time at which she finished her
homework = 06: 00+1: 30
= 7: 30
Hence, Raji finished her homework at 7 : 30 PM.
Question 20.
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:
Given, the time at which Alya goes out to play = 05: 30 PM and the duration of playing
= 1 hour 10 minutes
= 1: 10
So, the time at which she comes back
= 05 : 30 + 1 : 10
= 06 : 40
Hence, Alya comes back at 06:40 PM.
Question 21.
If the lunch break of a school starts at 12:30 PM and ends in 35 minutes, what time will lunch end?
Answer:
Given, the time at which lunch break start
= 12: 30 PM
and the duration of lunch
= 35 minutes
= 00: 35
So, the time at which lunch break ends
= 12: 30+00: 35
= 12: 65
= 01: 05
[∵ 60 minutes = 1 hour]
= 01: 05 PM
Question 22.
It is 08:35 PM right now. What time will it be after 8 hours and 25 minutes?
Answer:
Given, the present time
= 08: 35 PM
So, the time after 8 hours 25 minutes
= 08: 35+8: 25
= 04: 60
= 05: 00
[∵ 60 minutes = 1 hour]
Hence, the time will be 05: 00 AM.