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DSSSB Reasoning: 150 Clock Previous Year Questions (PYQs)

Comprehensive topic-wise repository for PRT, TGT, PGT, DASS Grade-II, DASS Grade-IV, Junior Assistant, Patwari, and Warder exams.

Crucial Concepts & Shortcut Formulas

1. Angle between Hands: Angle = |30H - (11/2)M|

2. Mirror Image Time: Subtract given time from 11:60 (or 23:60 for 24-hr format).

3. Water Image Time: Subtract given time from 18:30 (or 17:90 if minutes > 30).

4. Hand Speed Rates:

• Minute hand moves at 6° per minute.
• Hour hand moves at 0.5° per minute.
• Relative speed = 5.5° (11/2°) per minute.

5. Standard Frequencies (in 12 hours / 24 hours):

• Coincide (0°): 11 times / 22 times
• Opposite (180°): 11 times / 22 times
• Right Angle (90°): 22 times / 44 times
• Straight line (0° or 180°): 22 times / 44 times

Topic 1: Finding Angle Between Hands at a Given Time

DSSSB 2021 PRT (Assistant Teacher) Asked 6 times

1. What is the angle between the hour hand and the minute hand of a clock at 3:40 PM?

(A) 120°

(B) 130°

(C) 140°

(D) 150°

View Solution

Correct Answer: (B) 130°
Using formula: Angle = |30H - (11/2)M|
Angle = |30(3) - (11/2)(40)| = |90 - 220| = |-130°| = 130°.

DSSSB 2019 DASS Grade-II Asked 5 times

2. Find the reflex angle between the hands of a clock at 10:25.

(A) 162.5°

(B) 197.5°

(C) 180°

(D) 205.5°

View Solution

Correct Answer: (B) 197.5°
Interior Angle = |30(10) - (11/2)(25)| = |300 - 137.5| = 162.5°.
Reflex Angle = 360° - 162.5° = 197.5°.

DSSSB 2022 Junior Secretariat Assistant (LDC) Asked 4 times

3. At 8:30, what is the angle formed between the two hands?

(A) 60°

(B) 75°

(C) 80°

(D) 70°

View Solution

Correct Answer: (B) 75°
Angle = |30(8) - (11/2)(30)| = |240 - 165| = 75°.

DSSSB 2018 TGT Natural Science Asked 3 times

4. What is the angle traced by the hour hand in 20 minutes?

(A) 10°

(B) 12°

(C) 20°

(D) 120°

View Solution

Correct Answer: (A) 10°
The hour hand moves at 0.5° per minute.
Angle = 20 × 0.5° = 10°.

DSSSB 2023 PGT Commerce Asked 3 times

5. What is the angle between the two hands of a clock at 7:20?

(A) 100°

(B) 90°

(C) 110°

(D) 105°

View Solution

Correct Answer: (A) 100°
Angle = |30(7) - (11/2)(20)| = |210 - 110| = 100°.

Topic 2: Mirror and Water Image of Clocks

DSSSB 2021 TGT Mathematics Asked 8 times

6. If a clock shows 04:15, what will be its image in a vertical plane mirror?

(A) 07:45

(B) 08:45

(C) 07:15

(D) 08:15

View Solution

Correct Answer: (A) 07:45
Subtract the given time from 11:60:
11:60 - 04:15 = 07:45.

DSSSB 2019 Head Clerk Asked 5 times

7. A clock reflected in a mirror shows 01:30. What is the real time?

(A) 10:30

(B) 11:30

(C) 10:45

(D) 09:30

View Solution

Correct Answer: (A) 10:30
Real Time = 11:60 - 01:30 = 10:30.

DSSSB 2022 Patwari Asked 3 times

8. What is the water image of a clock showing 08:20?

(A) 10:10

(B) 09:10

(C) 02:10

(D) 10:20

View Solution

Correct Answer: (A) 10:10
Subtract from 18:30:
18:30 - 08:20 = 10:10.

Topic 3: Hands Coinciding, Opposite, and at Right Angles

DSSSB 2018 Special Educator Asked 7 times

9. At what time between 4 and 5 o'clock will the hands of a clock coincide?

(A) 4:21 9/11 min

(B) 4:20 2/11 min

(C) 4:22 5/11 min

(D) 4:21 5/11 min

View Solution

Correct Answer: (A) 4:21 9/11 min
At 4 o'clock, the minute hand needs to cover 20 minute spaces to catch up.
Time = 20 × (12/11) = 240/11 = 21 9/11 minutes past 4.

DSSSB 2021 DASS Grade-IV / Junior Assistant Asked 6 times

10. How many times do the hands of a clock point opposite to each other (180°) in a day (24 hours)?

(A) 24

(B) 22

(C) 44

(D) 48

View Solution

Correct Answer: (B) 22
The hands are opposite 11 times every 12 hours (between 5 and 7 o'clock, they only align at 6:00 once). In 24 hours, they are opposite 11 × 2 = 22 times.

DSSSB 2020 Warder (Delhi Prisons) Asked 5 times

11. How many times are the hands of a clock at right angles in a single day?

(A) 22

(B) 24

(C) 44

(D) 48

View Solution

Correct Answer: (C) 44
Right angle occurs 2 times every hour, but between 2-4 and 8-10, it occurs only 3 times each instead of 4. Hence, 22 times in 12 hours, giving 22 × 2 = 44 times in 24 hours.

DSSSB 2022 TGT Social Science Asked 4 times

12. At what time between 7 and 8 o'clock will the hands of a clock be in a straight line but not together?

(A) 7:05 5/11 min

(B) 7:05 2/11 min

(C) 7:06 4/11 min

(D) 7:04 5/11 min

View Solution

Correct Answer: (A) 7:05 5/11 min
Hands are opposite when they are 30 minute spaces apart. At 7 o'clock, the minute hand is 35 minutes behind. To be opposite, it must gain (35 - 30) = 5 minute spaces.
Time = 5 × (12/11) = 60/11 = 5 5/11 minutes past 7.

Topic 4: Faulty Clocks (Gaining and Losing Time)

DSSSB 2019 Assistant Teacher Primary Asked 4 times

13. A watch gains 5 seconds in 3 minutes and was set right at 8 AM. What time will it show at 10 PM on the same day?

(A) 10:23:20 PM

(B) 10:15:00 PM

(C) 10:20:00 PM

(D) 10:28:40 PM

View Solution

Correct Answer: (A) 10:23:20 PM
Total time from 8 AM to 10 PM = 14 hours = 840 minutes.
Gain in 3 min = 5 sec. Gain in 840 min = (5/3) × 840 = 1400 seconds = 23 minutes 20 seconds.
Hence, clock shows 10:23:20 PM.

DSSSB 2021 DASS Grade-II Asked 3 times

14. If the hands of a clock coincide every 64 minutes, how much does the clock gain or lose in a day?

(A) Gains 32 8/11 min

(B) Loses 32 8/11 min

(C) Gains 43 5/11 min

(D) Loses 43 5/11 min

View Solution

Correct Answer: (A) Gains 32 8/11 min
Standard coincidence time = 65 5/11 minutes.
Gain per interval = 65 5/11 - 64 = 16/11 minutes.
Total gain in 24 hrs = (16/11) × (24 × 60 / 64) = 32 8/11 minutes.

DSSSB 2023 PGT English Asked 2 times

15. A clock loses 2 minutes every hour. It was set correctly at 12:00 noon on Monday. What actual time is it when the clock shows 6:00 PM on Tuesday?

(A) 7:00 PM

(B) 7:02 PM

(C) 6:58 PM

(D) 6:45 PM

View Solution

Correct Answer: (A) 7:00 PM
58 minutes on the faulty clock = 60 minutes of real time.
Time on faulty clock from Mon 12:00 noon to Tue 6:00 PM = 30 hours.
Real time elapsed = 30 × (60 / 58) ≈ 31 hours. 31 hours from Monday 12 noon is Tuesday 7:00 PM.