Quantitative Aptitude · Reasoning

Time and Clocks

491 Questions

Time and clocks problems evaluate quantitative aptitude by testing concepts on clock gains, losses, and relative speeds of hands. Questions also cover global time zones and standard time calculations. These logical reasoning topics frequently appear in SSC and banking exams.

Clock gain or lossTime zonesAngle between handsStandard time calculationPrecise time measurement

Time and Clocks Questions

Multiple choice general knowledge math & puzzles

If 2 hours ago it was as long after one o'clock in the afternoon as it was before one o'clock in the morning. What time would it be now?

  1. 1 o Clock

  2. 12 o Clock

  3. 3 o Clock

  4. 9 o Clock
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The midpoint between 1 PM (13:00) and 1 AM (01:00) is 7 PM (19:00). If 2 hours ago it was 7 PM, then the current time is 9 PM. This satisfies the condition that 7 PM is 6 hours after 1 PM and 6 hours before 1 AM.

Multiple choice general knowledge math & puzzles

Lowell started his homework at 5:00pm. He spent 45 minutes on English, 35 minutes on math, and 1 hour 15 minutes on history. At what time did he finish all his homework?

  1. 0.815972222222222

  2. 0.770833333333333

  3. 0.763888888888889

  4. 0.8125
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Total time spent: 45m + 35m + 75m = 155 minutes (2 hours 35 minutes). Starting at 5:00 PM, he finishes at 7:35 PM. In Excel/decimal time format, 7:35 PM (19:35) is 19.5833/24 ≈ 0.81597. Option 68581 correctly represents this decimal time.

Multiple choice general knowledge math & puzzles

There are two candles of equal lengths and of different thickness. The thicker one lasts of six hours. The thinner 2 hours less than the thicker one. Ramesh lights the two candles at the same time. When he went to bed he saw the thicker one is twice the length of the thinner one. How long ago did Ramesh light the two candles

  1. 3 hour

  2. 4 hour

  3. 5 hour

  4. none
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The thicker candle burns at 1/6 per hour, the thinner at 1/4 per hour (since it lasts 2 hours less). Let t be the burning time. Remaining: thicker = 1 - t/6, thinner = 1 - t/4. When thicker is twice thinner: 1 - t/6 = 2(1 - t/4). Solving: 1 - t/6 = 2 - t/2, giving t/2 - t/6 = 1, so t/3 = 1, meaning t = 3 hours.

Multiple choice general knowledge math & puzzles

Lowell started his homework at 5:00pm. He spent 45 minutes on English, 35 minutes on math, and 1 hour 15 minutes on history. At what time did he finish all his homework?

  1. 0.815972222222222

  2. 0.770833333333333

  3. 0.763888888888889

  4. 0.8125
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Convert each time to hours and add: 45 min = 0.75 hr, 35 min ≈ 0.5833 hr, 1 hr 15 min = 1.25 hr. Total ≈ 2.5833 hours. Starting at 5:00 PM (17:00 in decimal hours), finishing time ≈ 19.5833. Converting back: 0.5833 × 24 ≈ 14 hours, or approximately 7:35 PM. Option A (≈0.816 of a day) represents the finishing time as a fraction of the day.

Multiple choice general knowledge math & puzzles

There are two candles of equal lengths and of different thickness. The thicker one lasts of six hours. The thinner 2 hours less than the thicker one. Ramesh lights the two candles at the same time. When he went to bed he saw the thicker one is twice the length of the thinner one. How long ago did Ramesh light the two candles

  1. 3 hour

  2. 4 hour

  3. 5 hour

  4. none
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let length be L. Thicker burns at L/6 per hour; thinner at L/4. After time t, remaining lengths are L(1-t/6) and L(1-t/4). Setting (1-t/6) = 2(1-t/4) gives 1-t/6 = 2-t/2. Solving for t: t/2 - t/6 = 1, so t/3 = 1, meaning t = 3 hours.

Multiple choice general knowledge math & puzzles

Suppose we have three traffic light changing after 36,42 and 72 sec respectively. If the light had been switched on at 9:00 A.M sharp, at what time will they change simultaneously.

  1. 9:08:04 a.m

  2. 9:08:06 a.m

  3. 9:08:24 a.m

  4. 9:08:30 a.m
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The lights change simultaneously at intervals equal to the LCM of 36, 42, and 72 seconds. LCM(36,42,72) = 504 seconds = 8 minutes 24 seconds. Starting at 9:00 AM, they will change together again at 9:08:24 AM. To find LCM: 36=2^2×3^2, 42=2×3×7, 72=2^3×3^2, so LCM=2^3×3^2×7=504.

Multiple choice general knowledge science & technology

What type of clock was first introduced by the US National Bureau of Standards in 1949?

  1. Atomic Clock

  2. Big Ben Alarm Clock

  3. Quartz clock

  4. Twelve O'Clock
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The first atomic clock, an ammonia maser, was developed at the US National Bureau of Standards (now NIST) and introduced in 1949. This groundbreaking invention revolutionized timekeeping by using atomic vibrations as the frequency standard, providing unprecedented accuracy.

Multiple choice general knowledge math & puzzles

Byomkesh then interrogates the guard to check whether he has monitored the vault right or not. The guard says that he monitors with full punctuality. Given the camera is on only for 30 second every 29 minute 30 second(cost cutting in bank: D). the power fluctuation in area is every 49 minutes after 9 and the power remains down for 1 minute. The first monitoring of camera started at 9:30. Help byomkesh in calculating if guard is telling the truth. Power went down first at 9:50.

  1. we cant say whether the guard is lying or not.

  2. The guard is telling the truth as the camera was on then,

  3. The guard is lying cause the camera was off then

  4. The guard must be lying as he must have slept.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The camera schedule starts at 9:30, then every 30 minutes: 10:00, 10:30, 11:00... Power goes down every 49 minutes after 9:00, first at 9:50 for 1 minute, then 10:39, 11:28, etc. At 10:00 (camera on), power is ON (from 9:51 to 10:38). At 10:30 (camera on), power is ON. At 10:39 (power off), camera would be OFF. At 11:00 (camera on), power is ON (from 10:40 to 11:27). However, by counting cycles, at 10:00 camera time would have power off from 9:49-9:50, but camera is only on 30 seconds starting at 9:59:30. By 11:38, the pattern shows camera was on during power outages, proving the guard lied.

Multiple choice general knowledge math & puzzles

If a clock is showing 8:15 through a mirror, then what is the actual time??

  1. 4:45

  2. 2:15

  3. 4:15

  4. 3:45
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

For a mirror image of an analog clock showing time h:m (where h < 12), the actual time is (11-h):(60-m). For 8:15, we calculate (11-8):(60-15) = 3:45. This works because mirror images appear reversed, and the sum of the actual time and mirror time equals 11:60 (which is equivalent to 12:00). Option D is correct. Option C would be correct if we simply subtracted from 12:00 without accounting for minutes.

Multiple choice general knowledge

Geography: What is the time difference between India and Australia?

  1. Australia is 5.25 hrs ahead.

  2. Australia is 11.25 hrs ahead.

  3. Australia is 8.25 hrs ahead.

  4. Australia is 3.25 hrs ahead.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

India (IST, UTC+5:30) is approximately 3.25 hours behind Australia's eastern states (AEST, UTC+10). This means when it's morning in India, it's afternoon in Australia. Note: Australia has multiple time zones, but the eastern states are the most common reference.

Multiple choice general knowledge

The Indian Standard Time (IST) is

  1. 6 Hrs + GMT

  2. 5 1/2 Hrs + GMT

  3. 5 1/2 Hrs - GMT

  4. 6 Hrs - GMT
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Indian Standard Time (IST) is calculated based on the 82.5°E longitude. Since the Earth rotates 15° per hour, 82.5° translates to exactly 5 hours and 30 minutes. Because India is east of the Prime Meridian, IST is ahead of (+), not behind (-), Greenwich Mean Time (GMT).

Multiple choice general knowledge math & puzzles

There are two candles of equal lengths and of different thickness. The thicker one lasts of six hours. The thinner 2 hours less than the thicker one. Ramesh lights the two candles at the same time. When he went to bed he saw the thicker one is twice the length of the thinner one. How long ago did Ramesh light the two candles

  1. 7 hours

  2. 3 hours

  3. 4 hours

  4. 2 hours
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Thicker candle burns in 6h, thinner in 4h. Let t be the time passed. (1 - t/6) = 2 * (1 - t/4). 1 - t/6 = 2 - t/2. t/2 - t/6 = 1. t/3 = 1. t = 3 hours.

Multiple choice general knowledge math & puzzles

There are two candles of equal lengths and of different thickness. The thicker one lasts of six hours. The thinner 2 hours less than the thicker one. Ramesh lights the two candles at the same time. When he went to bed he saw the thicker one is twice the length of the thinner one. How long ago did Ramesh light the two candles

  1. 7 hours

  2. 3 hours

  3. 4 hours

  4. 2 hours
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let length be L. Thicker rate = L/6, Thinner rate = L/4. After time t, Thicker = L - Lt/6, Thinner = L - Lt/4. Equation: L - Lt/6 = 2(L - Lt/4). Solving for t gives 3 hours.

Multiple choice general knowledge

What is the primary reasons that 02:00 in the morning was set as that changeover time in the United States?

  1. It would be convenient since a lot of people would be up partying

  2. It was easy to calculate the change from this time

  3. Less disruption and most would be changed over by daybreak

  4. The time would force people to remember that the change was happening
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

To answer this question, the user needs to know the historical background of the changeover time in the United States from Standard Time to Daylight Saving Time.

Option A is incorrect because the changeover time was not set to accommodate partygoers.

Option B is incorrect because although 02:00 is an easy time to calculate, it was not the primary reason for selecting that time.

Option C is the correct answer. One of the primary reasons for setting 02:00 as the changeover time in the United States was to cause less disruption, as most people would be asleep by that time, and the changeover would be complete by daybreak.

Option D is also incorrect because the primary reason for selecting 02:00 as the changeover time was not to force people to remember the change.

Therefore, The Answer is: C