Exercise 2.2

Exercise 2.2

1. Say the time in two ways:

Answer:

(i) 10:15 hours; quarter past 10

(ii) 6:45 hours; quarter to 7

(iii) 4:10 hours; 10 minutes past 4

(iv) 3:30 hours; half past 3

(v) 9:40 hours; 20 minutes to 10

2. Match the following:

(i) 9.55     a. 20 minutes past 2

(ii) 11.50   b. quarter past 4

(iii) 4.15    c. quarter to 8

(iv) 7.45    d. 5 minutes to 10

(v) 2.20     e. 10 minutes to 12

Answer: (i) d   (ii) e   (iii) b     (iv) c  (v) a

(i) 9.55 d. 5 minutes to 10

(ii) 11.50 e. 10 minutes to 12

(iii) 4.15 b. quarter past 4

(iv) 7.45 c. quarter to 8

(v) 2.20 a. 20 minutes past 2

3. Convert the following:

(i) 20 minutes into seconds

20 minutes = (20 × 60) seconds

60 seconds = 1 mt

= 1200 seconds

(ii) 5 hours 35 minutes 40 seconds into seconds

5 hours 35 minutes 40 seconds

(5 × 60 × 60) seconds + (35 × 60) seconds + 40 seconds

18000 seconds + 2100 seconds + 40 seconds

20140 seconds 

(iii) 3 ½ hours into minutes

3 ½ hours = 3 hours 30 minutes

= (3 × 60 ) minutes + 30 minutes

= 180 minutes + 30 minutes 9 hrs

'= 210 minutes

(iv) 580 minutes into hours

580 minutes = (580 ÷  60) hours 

 = 9 hours 40 minutes.  

(v) 25200 seconds into hours

25200 seconds = (25200 ÷ 3600) hours

= 7 hours.

4. The duration of electricity consumed by the farmer for his pumpset on Monday and Tuesday was 7 hours 20 minutes 35 seconds and 3 hours 44 minutes 50 seconds respectively. Find the total duration of consumption of electricity.

Total duration of consumption of electricity = 11 hrs 5 mts 25 secs.

5. Subtract 10 hours 20 minutes 35 seconds from 12 hours 18 minutes 40 seconds

1 hour 58 minutes 5 seconds. 

6. Change the following into 12 hour format

(i) 02:00 hours

(ii) 08:45 hours

(iii) 21:10 hours

(iv) 11:20 hours

(v) 00:00 hours

(i) 02:00 hours = 2 a.m

(ii) 08:45 hours = 8:45 a.m

(iii) 21:10 hours = 9:10 p.m

(iv) 11:20 hours = 11:20 a.m

(v) 00:00 hours = 12 midnight

7. Change the following into 24 hour format

(i) 3.15 a.m

(iii) 12.35 p.m

(iv) 12.00 noon

 (v) 12.00 midnight

(i) 3.15 a.m = 3:15 hours

(ii) 12.35 p.m = 12:35 hours

(iii) 12.00 noon = 12:00 hours

(iv) 12.00 midnight = 00:00 (or) 24:00 hours

8. Calculate the duration of time

(i) from 5.30 a.m to 12.40 p.m

12.40 p.m = 12.40 hours

5.30 a.m = 5.30 hours

Duration of Time = 7.10 hours

(ii) from 1.30 p.m to 10.25 p.m

10.25 p.m = 22.25 hours (10.25 + 12.00) hrs.

1.30 a.m   = 13.30 hours (1.30 + 12.00) hrs.

Duration of Time = 8.55 hours

(iii) from 20:00 hours to 4:00 hours

4:00 hours = 28.00 hours (4 + 24) hrs.

20 hours = 20.00 hours

Duration of Time = 8.00 hours

Duration of Time = 8 hours

(iv) from 17:00 hours to 5:15 hours

5:15 hours = 29.15 hours (5.15 + 24) hours

17:00 hours = 17.00 hours

Duration of Time = 12.15 hours

Duration of Time = 12 hours 15 minutes

9. The departure and arrival timing of the Vaigai Superfast Express (No. 12635) from Chennai Egmore to Madurai Junction are given. Read the details and answer the following

(i) At what time does the Vaigai Express start from Chennai and arrive at Madurai?

Vaigai Express starts at 13:40 hours from Chennai and arrives at 21:20 hours at Madurai.

(ii) How many halts are there between Chennai and Madurai?

8 halts are there between Chennai and Madurai.

(iii) How long does the train halt at the Villupuram Junction?

The train halts at Villupuram junction = 15:55 − 15:50 = 0.05 hours

= 5 minutes

(iv) At what time does the train come to Sholavandan?

The train comes to Sholavandan at 20:34 hours.

(v) Find the journey time from Chennai Egmore to Madurai?

Total journey time =  7 40

Total journey time =  7 hours 40 minutes

10. Manickam joined a chess class on 20.02.2017 and due to exam, he left practice after 20 days. Again he continued practice from 10.07.2017 to 31.03.2018. Calculate how many days did he practice?

Months  : Days

July (31−9) … 22

August … 31

September … 30

October … 31

November … 30

December … 31

January … 31

February … 28 (2018 is an ordinary year)

March … 31  

Total :    265

Number of days practiced from 20−02−2017 ... 20

Total number of days he practiced 285

11. A clock gains 3 minutes every hour. If the clock is set correctly at 5 a.m, find the time shown by the clock at 7 p.m?

7 p.m = 19 hours (7+12) hours

5 a.m. = 5 hours

Duration = 14 hours

For 1 hour clock gains = 3 minutes

For 14 hours the clock gains =14 × 3 minutes

= 42 minutes

At 7 p.m the clock shows the time 7 hours 42 minutes.

12. Find the number of days between the Republic day and Kalvi Valarchi Day in 2020.

Republic day January 26th

Kalvi Valarchi Day July 15th

Months : Days

January (31 − 25) … 6

February … 29 (2020 is a leap year)

March … 31

April … 30

May … 31

June ... 30

July ... 15

Total number of Days ... 172

13. If 11th of January 2018 is Thursday , what is the day on 20th July of the same year

Months : Days

January (31−10) … 21

February … 28 (2018 is an ordinary year)

March … 31

April … 30

May … 31

June … 30

July … 19

Total Days ... 190

190 days ÷ 7 = 27 weeks + 1 day.

The next day of Thursday is Friday.

July 20th is the Friday.

14. (i) Convert 480 days into years.

480 days = (480 ÷ 365) years

= 1 year 115 days

= 1 year (115 ÷ 30) months

= 1 year 3 months 25 days

480 days = 1 year 3 months 25 days

(ii) Convert 38 months into years.

38 months = (38 ÷ 12) years

= 3 years 2 months

38 months = 3 years 2 months

15. Calculate your age as on 01.06.2018

Date of Birth             :   01−01−2006

From 2006 to 2018   : 12 years

From January to May : 5 months

June                            : 1 day

My age is 12 years 5 months 1 day

Objective Type Questions

16. 2 days = _——— hours.

a) 38

 b) 48

c) 28

d) 40

Answer: b) 48

17. 3 weeks = _——— days

a) 21

b) 7

c) 14

d) 28

Answer: a) 21

18. Number of ordinary years between two consecutive leap years is _{——————}

a) 4 years

b) 2 years

c) 1 year

d) 3 years

Answer: d) 3 years

19. What time will it be 5 hours after 22:35 hours

a) 2:30 hours

b) 3:35 hours

c) 4:35 hours

d) 5:35 hours

Answer: b) 3:35 hours            

20. 2 ½ years is equal to _{——————} months.

a) 25

b) 30

c) 24

d) 5

Answer: b) 30

ANSWERS:

Exercise: 2.2

1. i) 10:15 hours; quarter past 10

ii) 6:45 hours ; quarter to 7

iii) 4:10 hours ; 10 minutes past 4

iv) 3:30 hours; half past 3

v) 9:40 hours; 20 minutes to 10;

2. i. (d)      ii. (e)       iii. (b)          iv. (c)      v. (a)

3. i) 1200 seconds      ii) 20140 seconds    iii) 210 minutes          iv) 9 hours 40 minutes v) 7 hours

4. 11 hours 5 minutes 25 seconds

5. 1 hour 58 minutes 5 seconds

6. i) 2 a.m ii) 8:45 a.m iii) 9:10 p.m iv) 11:20 a.m  v) 12 midnight

7. i) 3:15 hours      ii) 12:35 hours iii) 12:00 hours     iv) 00:00 or 24:00 hours

8. i) 7 hours 10 minutes

ii) 8 hours 55 minutes

iii) 8 hours

iv) 12 hours 15 minutes

9. i) 13:40 hours , 21:20 hours ii) 8 halts iii) 5 minutes  iv) 20:34 hours v) 7 hours 40 minutes

10. 285 days

11. 7 hour 42 minutes

12. 172 days

13. Friday

14. (i) 1 year 3 months 25 days  (ii) 3 years 2 months

Objective Type Questions

16. (b) 48

17. (a) 21

18. (d) 3

19. (b) 3:35 hours

20. (b) 30