Quantitative Aptitude

Clocks and Calendars

428 Questions
All Angle between hands 150 Clock gaining or losing time 132 Clock hands coincidence 69 Right angle times 30 Find time from angle 21 Decoding mixed date formats 7 Find day using reference date 6 Repeating same calendar 6 Date without reference day 3

Clocks and Calendars Questions

Multiple choice

If your wrist watch was slow by 3 minutes at 8:00 a.m. on Saturday and was fast by 5 minutes at 2:00 p.m. on Sunday, when did your watch show the correct time?

  1. 6:45 p.m. on Sunday

  2. 7:15 p.m. on Saturday

  3. 6:15 p.m. on Sunday

  4. 4:45 p.m. on Sunday
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The total time from Saturday 8:00 a.m. to Sunday 2:00 p.m. is 30 hours. The watch gains 8 minutes (3 slow to 5 fast) in 30 hours. The watch shows the correct time when it has gained exactly 3 minutes, which takes (3/8) * 30 = 11.25 hours. 11.25 hours after Saturday 8:00 a.m. is 7:15 p.m. on Saturday.

Multiple choice

A watch which gains 10 seconds in 5 minutes was set correct at 9 a.m. When the watch indicates 20 minutes past 7 O'clock the same evening, the true time is

  1. 7 p.m.

  2. 7.40 p.m.

  3. 7.10 p.m.

  4. 8 p.m.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The watch gains 10 seconds in 5 minutes, which is 2 seconds per minute. In 1 hour (60 mins), it gains 120 seconds (2 minutes). The watch shows 7:20 p.m. starting from 9 a.m., which is 10 hours and 20 minutes = 620 minutes. The watch gains 2 seconds for every 60 seconds of true time, so it runs at a ratio of 62/60. True time = 620 * (60/62) = 600 minutes. 600 minutes = 10 hours. 9 a.m. + 10 hours = 7 p.m.

Multiple choice

My watch, which gains uniformly, is 2 minutes behind at noon on Saturday. It is 4 minutes and 48 seconds ahead at 3:00 p.m. the following Monday. When does it show the correct time?

  1. 3:00 a.m. Sunday

  2. 1:00 a.m. Sunday

  3. Midnight Monday

  4. 1:00 a.m. Monday
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Total time from Sat noon to Mon 3pm is 51 hours. Total gain = 2 min + 4 min 48 sec = 6.8 minutes. Gain per hour = 6.8 / 51 = 2/15 minutes per hour. To show correct time, it must gain 2 minutes. Time taken = 2 / (2/15) = 15 hours. 15 hours after Sat noon is Sun 3 a.m.

Multiple choice

If the current time is 6:20, then after how much time will the hands of the clock make the same angle as they do at present?

  1. 20 minutes

  2. 10 minutes

  3. 25 5 11 minutes

  4. 35 5 11 minutes

  5. 15 5 11 minutes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

At 6:20, the angle between hands is |30*6 - 5.5*20| = |180 - 110| = 70 degrees. The hands make the same angle when the minute hand is 70 degrees behind or ahead of the hour hand. This occurs after 70 / (5.5) = 140/11 = 12 8/11 minutes, or when the hands overlap and move to the same relative position.

Multiple choice

Arjun goes out for some time between 5 o'clock and 6 o'clock and returns between 6 o'clock and 7 o'clock. He notices that the hands of the clock have exactly interchanged their positions. At what approximate time did Arjun go out?

  1. 36 minutes past 5 o'clock

  2. 34 minutes past 5 o'clock

  3. 32 minutes past 5 o'clock

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let the time be 5:x and 6:y. The positions of hands interchange. The minute hand at x minutes past 5 is at 6x degrees from 12. The hour hand at y minutes past 6 is at 180 + 0.5y degrees. Solving the system yields approximately 32 minutes.

Multiple choice

The clock at Ravi's house loses 3 minutes daily and his office clock gains 4 minutes daily. They are set right at 3 p.m. What time will the slower clock indicate the next day, when the office clock shows 9 p.m?

  1. 8:51 p.m.

  2. 8:55 p.m.

  3. 8:43 p.m.

  4. 8:58 p.m.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The clocks are set at 3 p.m. The office clock shows 9 p.m. the next day, which is 30 hours later. In 30 hours, the office clock gains 4 minutes/24 hours * 30 hours = 5 minutes. The actual time is 9 p.m. - 5 minutes = 8:55 p.m. The slower clock loses 3 minutes/24 hours * 30 hours = 3.75 minutes. So it shows 8:55 p.m. - 3.75 minutes = 8:51.25 p.m.