In this post we will discuss logical reasoning questions related to clocks. Clock is one of the important chapter of verbal ability syllabus and lot of questions are frequently asked in the competition exams.
In order to solve questions fast, try to draw picture in your mind how clock needles move
1. Minute hand travels 360 degree in 60 minutes
==> So, Minute hand moves 6 degree in 1 minute
2. Hour hand moves 360 degree in 12 hours
==> So, Hour hand moves 30 degree in 1 hour
==> Also, Hour hand moves 0.5 degree in 1 minute
Try to remember the above points, it will help you solve questions faster.
Clock Questions Verbal Ability
(Q.1) The minute hand of clock overtakes the hour hand at intervals of 64 minute of correct time. How much a day clock gain or lose ?
(a) 360/11 minutes
(b) 360/12 minutes
(c) 360/13 minutes
(d) 360/14 minutes
Remember that in ideal watch, the minute hand overtakes hour hand in 65\frac { 5 }{ 11 } minutes
But in this watch minute hand overtakes hour hand in 64 minutes
This means that the watch is moving fast
We can calculate how fast the watch is moving by following calculation
==> Ideal Watch Time – Watch Time
==> 65(5/11) – 64
==> \frac { 16 }{ 11 }
Hence for every 64 minutes, the clock is moving 16/11 minute fast
==> In 64 minutes clock gains => 16/11 minutes
==> In 1 minute clock gain=> 16/11 * 1/64
==> In 1 day clock gains => 16/11 * 1/64 * 60 *24 minutes ==> 360/11 minutes
Hence in 1 day, the clock gains 360/11 minutes
option (a) is the right answer
(Q.2) A clock is set right at 8 a.m. on Sunday. It gains 8 mins in 24 hours. What is the correct time when the clock indicates 9 p.m. on upcoming Sunday ?
(a) 9 PM
(b) 8 PM
(c) 11 PM
(d) 7 PM
Total hours from Sunday 8 a.m. to next Sunday 9 PM = 181 hours
According to question the clock gains 8 min. in 24 hours
==>24 hours ideal time => clock gained 8 mins
==> 24 hours ideal time ==> 24 hours + 8 mins (clock time)
==> 24 hours + 8/60 hrs
==> 362/15 hours
Hence in 24 hours, the clock covers 362/15 hours
So, in 1 hour, the clock gained ==> \frac { 362 }{ 15 \quad \times \quad 24 }
Now in 181 hours, the clock covers ==>
\frac { 362\quad \times \quad 181 }{ 15\quad \times \quad 24 }
==> 182 hours
So in this time period, our clock is fast by = 182-181 = 1 hours
From the above calculation we can see that in the given time period, the clock is fast by 1 hour
so on next Sunday, if the clock is showing 9 PM, it means that the actual time is ==> 9 – 1 => 8 PM
So, 8 PM is the real time
option (b) is the right answer
Q.3 A clock is set right at 10 a.m. on Sunday it loses 8 mins. In 24 hours. What is the correct time when the clock indicates 9 p.m. on next Sunday ?
(a) 9 PM
(b) 8 PM
(c) 11 PM
(d) 10 PM
Total hours of clock from 10 a.m. Sunday to 9 p.m. on following Sunday = 179 hours
According to question , the looses 8 min in 24 hours
In 24 hours ideal time, the clock covers
=> 24 hours – 8 min. = 23 hours 52 min.
==> 23 + 52/60
==> 345 + 13 / 15
=> 358/15 hours of given clock
Hence in 24 hours, the clock covers = 358/15 hours
358/15 hours of given clock = 24 hours of correct clock
1 hour of given clock = 24 X 15/358 hours of correct clock
179 hours of given clock = 24X15X179 / 358 = 180 hours of correct clock
It means 1 hour more
Correct time = 9 p.m. + 1 hour = 10 p.m.
Option (d) is the right answer
(Q.4) A watch which gains uniformly is 4 min. slow at 9 a.m. on Sunday, and is 4 min 15 sec. fast at 9 p.m. on upcoming Friday. When was it correct ?
(a) 1:00 AM
(b) 4:00 AM
(c) 5:00 AM
(d) 2:00 AM
Time period is between Sunday 9 a.m. and upcoming Friday 9 p.m. (total 132 hours)
Total watch gains 4 min + 4 min 15 sec => 8 min 15 sec
Converting into minutes
==> 8 + 15/60 = 8 + ¼ = 33/4 min.
Hence in 132 hours the clock gained 33/4 minutes
Total hours = 132 hours
33/4 min gain in 132 hours
1 minute gain in = 132 X 4 / 33 hours
As the clock was slow 4 minutes, total time taken to get into right time
4 minute gain in==> 132 X 4 X 4 / 33 ==> 64 hours
Hence in 64 hours, the clock will gain 4 minute and get into right time
9 a.m. Sunday + 64 hours = 9 a.m. Sunday + 2 days 16 hours = 1 a.m. Wednesday
In 1:00 AM Wednesday, the clock will show right time.
option (a) is the right answer
(05) After 9’0 clock at what time between 9 p.m and 10 p.m will the hour and minute hands of a clock point in opposite direction?
(a)15 minutes past 9
(b)16 minutes past 9
(c) 16 \frac{4}{11} minutes\ past\ 9
(d) 17 \frac{4}{11} minutes\ past\ 9 \\ \\
Read Solution
Using the Formula
\theta =30H-\frac{11}{2} M
Where
H = Hour Hand
M = Minute Hand
\theta = Angle between Minute hand and Hour hand
Now H=9
\theta =180\degree \ (since\ hands\ are\ in\ opposite\ direction) \\\ \\
⟹ 180=30\times 9-\frac{11}{2} \times M \\ \\
⟹ 180=\frac{540-11M}{2} \\ \\
⟹ 360=540-11M \\ \\
⟹ 11M=180 \\ \\
⟹ M=\frac{180}{11} =16.36\ min \\ \\
⟹ 16\frac{4}{11} \ minutes\ past\ 9
option (c) is the right answer
(06) At what time are the hand of clock together between 6 and 7?
(a) 32\frac{8}{11} \ minutes\ past\ 6 \\\ \\ (b) 34\frac{8}{11} \ minutes\ past\ 6 \\\ \\ (c) 30\frac{8}{11} \ minutes\ past\ 6 \\\ \\ (d) 32\frac{5}{7} \ minutes\ past\ 6 \\ \\ Read SolutionTo overlap the minute hand has to gain 30 minutes.
We know that:
In 60 minutes, Minute hand cover 360 degrees,
In 60 minutes, Hour hand cover 30 degrees,
Hence in every 60 min. minute hand cover 330 degrees more than the hour hand
Also, 330 degrees = 55 min. in clock
So, in every 60 min. minute hand is 55 min. ahead of hour hand
So the hands will overlap e 32\frac{8}{11} minutes past 6
Option (a) is the right answer
(07) A clock goes fast by one minute during the first hour, by two minutes at the end of second hour, by 4 minutes at the end of 3rd hour, by 8 minutes by the end of 4th hour, and so on. At the emd of which hour, will it be fast by just over sixty minutes?
a) fifth
b) sixth
c) seventh
d) eighth
First hour ⟹ 1 min
Second hour ⟹ 2 min
Third hour ⟹ 4 min
Fourth hour ⟹ 8 min
Fifth hour ⟹ 16 min
Sixth hour⟹ 32 min
Seventh hour ⟹ 64 min
Hence at the end of 7th hour it will be fast by just over 60min
Option (c) is the right answer
(08) A clock goes slow from midnight by 5 min. at the end of the 1st hour, by 10 min. at the end of the 2nd hour, by 15 min. at the end of the 3rd hour and so on. What will be the time by this clock after 6 hours?
a) 6:00am
b) 5:30am
c) 6:30am
d) 5:15am
Clock is getting slow by 5 min per hour from midnight,
So, after 6 hours clock will go slow by =
Time shown by the clock = 6:00 – 0:30= 5:30 am
Option (b) is the right answer
(09) A clock only with dots marking 3,6,9 and 12 0′ clock positions has been kept upside down in front of mirror. A person reads the time in the reflection of the clock as 12:30. What is the actual time?
(a) 12 O’ clock
(b) 12:30
(c) 6 O’ clock
(d) 03:45
For actual Time we have to subtract 12:30 from 17:90, because both hands of clock are between 6 to 12.
17:90-12:30=5:60=6:00
Concept: If hour hand lies between 6 to 12 and minute hand is lies between 6 to 12 then we have to subtract time from 17:90 to get actual time.
Option (c) is the right answer
(10) A clock only with dots marking 3,6,9 and 12 0′ clock positions has been kept upside down in front of mirror. A person reads the time in the reflection of the clock as 9.50. What is the actual time?
(a) 2:15
(b) 8:40
(c) 8:50
(d) 4:15
For actual Time we have to subtract 9:50 from 17:90, because both hands of clock are between 6 to 12.
17:90 – 9:50 = 8:40
Concept: If hour hand lies between 6 to 12 and minute hand is lies between 6 to 12 then we have to subtract time from 17:90 to get actual time.
Option (b) is the right answer