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

A clock which gains uniformly is 2 minutes behind at noon on Monday and is 4 minutes and 48 seconds ahead at 2 p.m. on the following Monday. When did it show the correct time?

  1. 2 p.m. on Tuesday

  2. 2 p.m. on Wednesday

  3. 3 p.m. on Thursday

  4. 1 p.m. on Friday
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The clock gains 2 + 4.8 = 6.8 minutes in 7 days + 2 hours = 170 hours. It needs to gain 2 minutes to show the correct time. Time taken = (2 / 6.8) * 170 hours = 50 hours. 50 hours from Monday noon is Wednesday 2 p.m.

Multiple choice

A watch that gains 20 seconds in 12 minutes was set right at 10:00 A.M. In the afternoon of the same day, when the watch indicated quarter past 7 o'clock, the true time is

  1. 7 P.M.

  2. 6 P.M.

  3. 5 P.M.

  4. 4 P.M.

  5. 8 P.M.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The watch gains 20 seconds every 12 minutes, which is 100 seconds per hour. From 10:00 A.M. to 7:15 P.M. is 9 hours and 15 minutes (9.25 hours). The total gain is 9.25 * 100 = 925 seconds, which is 15 minutes and 25 seconds. Subtracting this from 7:15 P.M. gives 6:59:35 P.M., which is closest to 7 P.M.

Multiple choice

A faulty watch gains time uniformly. It is 9 minutes behind at noon on Sunday and 3 minutes 30 seconds fast at 7:00 P.M. on the following Sunday. When was it showing the correct time?

  1. Sunday, 5:00 P.M.

  2. Sunday, 6:00 P.M.

  3. Friday, 6:00 P.M.

  4. Friday, 5:00 P.M.

  5. Saturday, 6:00 P.M.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total time elapsed from Sunday noon to next Sunday 7 PM = 7 days + 7 hours = 175 hours. Total gain = 9 min + 3.5 min = 12.5 min = 750 seconds. Rate of gain = 750/175 seconds/hour. To show correct time, it must gain 9 minutes (540 seconds). Time taken = 540 / (750/175) = 540 * 175 / 750 = 126 hours. 126 hours = 5 days and 6 hours. Sunday noon + 5 days 6 hours = Friday 6 PM.

Multiple choice

A clock loses 10 minutes after every hour. If it shows the correct time at 10 A.M. on Saturday on 1st March, 2020, then when will it show the correct time as 10 again?

  1. Tuesday, 4th March, 2020

  2. Wednesday, 5th March, 2020

  3. Thursday, 6th March, 2020

  4. Saturday, 8th March, 2020

  5. Sunday, 10th March, 2020
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For a losing clock to show the correct time again, it must lose a total of 12 hours, which is 720 minutes. Since the clock loses 10 minutes every hour, it will take 720 / 10 = 72 hours (or exactly 3 days) to show the correct time again. Adding 3 days to Saturday, 10 A.M. on 1st March, 2020, brings us to Tuesday, 10 A.M. on 4th March, 2020.