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Time difference - class-V

Description: time difference
Number of Questions: 41
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Tags: maths measuring time trip to the golkonda fort measurement of time time
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Write following $24$ hour times into $12$ hour times.
$3:50$

  1. $3:50$ am

  2. $3:50$ pm

  3. $3:50$

  4. $15:50$ pm


Correct Option: A
Explanation:

For $24$ hour time from $1:00$ to $11;59$ just mark $\text{am}$ to it to convert it into $12$ hour time.

$3:50=3:50 \ \text{am}$
Option A is correct.

Convert this $12$ hour time into $24$ hour time.
$9:20$ pm

  1. $9:20$ 

  2. $11:20$ 

  3. $19:20$

  4. $21:20$


Correct Option: D
Explanation:

To change a $pm$ time to $24$ hours time , you have to add $12 \ \ pm$ to the hours unless it is $12\ \ pm$ then the time remain unchanged .

$9:20\ \ pm=(9+12):20=21:20$ 
So option $D$ is correct.

Write following $24$ hour times into $12$ hour times.
$23:35$

  1. $11:35$

  2. $11:35$ am

  3. $11:35$ pm

  4. $23:35$ pm


Correct Option: C
Explanation:

To convert $24$ hour time from $13:00$ to $23:59$ into $12$ hour time just subtract $12$ from the hours and mark it as $\text{pm}$.

$23:35=(23-12):35 \ \text{pm}=11:35 \ \text{pm}$
Hence, the correct answer is $11:35\text{ pm}$.

Write following $12$ hour times into $24$ hour times.
$8:53$ pm

  1. $8:53$ am

  2. $8:53$ pm

  3. $20:53$

  4. $20:53$ pm


Correct Option: C
Explanation:

To change a $pm$ time to $24$ hours time , you have to add $12 \ \ pm$ to the hours unless it is $12\ \ pm$ then the time remain unchanged .

$8:53\ \ pm =(8+12):53=20:53$
Option $C$ is correct.

Marry put a roast in the oven at $2:45$ P.M. She cooked the roast for $3$ hours $48$ minutes. What time did Marry take the roast out of the oven?

  1. $5:36$ P.M.

  2. $6:21$ P.M.

  3. $6:33$ P.M.

  4. $7:30$ P.M.


Correct Option: C
Explanation:

This question becomes simply the question of addition and substraction of time.
$ \therefore $ $2: 45 + 3:48$ = $6:33 $

Write following $24$ hour times into $12$ hour times.
$12:00$

  1. $12:00$ am

  2. $12:00$ pm

  3. $12:00$

  4. $0:00$


Correct Option: B
Explanation:

For $2$ hours time from $12:00$ to $12:59$ just maark $\text{pm}$ to it to convert it into $12$ hour time.

$12:00=12:00$ pm
Hence, option B is correct.

A day has how many hours?

  1. $12$ hours

  2. $24$ hours

  3. $36$ hours

  4. $48$ hours


Correct Option: B
Explanation:

A day has $86400s=1440mins=24hrs$

Hence, the answer is $24$ hrs.

At 4.24 pm, how many degrees has the hour hand of a clock moved from its position at noon ?

  1. $132^{\circ}$

  2. $135^{\circ}$

  3. $140^{\circ}$

  4. $145^{\circ}$


Correct Option: A
Explanation:

The amount of degrees moved by the hour clock $=$
$=\dfrac{360}{12}(4+\dfrac{24}{60})$
$=120+12=132^\circ$

What percent of $1$ day is $36$ minutes?

  1. $25\%$

  2. $2.5\%$

  3. $3.6\%$

  4. $0.25\%$


Correct Option: B
Explanation:
Total hours in 1 day $=  24$ hrs
$1$ hour $= 60$ minutes
Total minutes in $1$ day $=  24 \times 60 = 1440$ minutes
Percent of $36$ min in $1$ Day is 
$= \dfrac{36}{1440} \times 100  \% = 2.5 \%$

What does a.m. and p.m. means respectively?

  1. Before and after midday

  2. After and before midday

  3. Before and after midnight

  4. After and before midnight


Correct Option: A
Explanation:
AM and PM both are Latin words, used in 12-hour clock system to represent Before Noon and After Noon. They are also represented as A.M. and P.M.
AM expand as Anti Meridiem which means "before midday" and PM expand as Post Meridiem which means "after midday".

Calculate the time shown on Varun's watch, when the actual time was half past $6$ in the evening.

  1. $5:30$ p.m

  2. $6:55$ p.m

  3. $6:30$ p.m

  4. $5:55$ p.m


Correct Option: A
Explanation:
With minutes 1 – 29, we say it’s past (or after) the hour.

Therefore, half past 6 means

$5:30pm$

Choose the most appropriate option.
The angles between the hands of a clock when the time is $4:25$ am is?

  1. $14.5$ degrees

  2. $12.5$ degrees

  3. $17.5$ degrees

  4. $13.5$ degrees


Correct Option: C
Explanation:
The hour hand rotates $0.5^o$ per minute while the minute hand rotates $6^o$ per minute.

At exactly four, the hour hand as completed $240$ minutes $= 120^o$. 

Hence angle between minute and hour hand at that point is $120^o$.

At $4:25,$ the minute hand has moved $25\times 6= 150^o.$

Thus angle between minute hand and $12$(on the clock) is $150^o.$

But at the same time, even the our hand has moved $0.5\times 25= 12.5^o.$

Now, the angle between the hour hand and $12$(on the clock) is $120+12.5=132.5^o$.

Now the angle between the two hands of the clock $=150^o-132.5^o$ 
                                                                                       $ = 17.5^o.$
                                                                       

Three bells in a temple toll at every $10$ minutes, $18$ minutes and $30$ minutes respectively. If they toll together at $7:00$ am , then the time among the following at which they will tool together again is 

  1. $1:30$ pm

  2. $2:30$ pm

  3. $3:30$ pm

  4. $3:00$ pm


Correct Option: A

A clock is set at  $5{ am }.$  If the clock loses  $16$  minutes in  $24$  hours, what will be the true time when the clock indicates  $10$  pm on  $4 th$  day?

  1. $9:30{ pm }$

  2. $11 pm$

  3. $10 pm$

  4. $10:30{ pm }$


Correct Option: A

Hari and Aman walk on a circular track and they take $120$ seconds and $150$ seconds respectively to complete one revolution. If they start together at $6:00$ AM from the starting point , then how many times will they meet between $6:05$ AM and $7:35$ AM?

  1. $6$

  2. $9$

  3. $12$

  4. $4$


Correct Option: A

A person has mistaken the image of a clock in a plain mirror as the clock and read the time as 6:10. What was the correct time?

  1. 6:50

  2. 5:50

  3. 5:10

  4. 7:50

  5. None


Correct Option: B
Explanation:

Assume that there is a line drawn between 12 and 6 on the clock, this can be a line of symmetry.
When we take the mirror image of this clock, the hands that are on the right side of this line will appear equidistant on the left side of the line and vice versa.
The time indicated is 6:10, the hour hand a little after 6 and the minute hand on 2.
Its mirror image will become, the hour hand a little before 6 and the minute hand on 10, i.e, 5:50.

A clock, which loses 5 minutes per day, is set to show the correct time at 12 noon on a Sunday. What time does the clock show at 12 noon on the next Sunday?

  1. 11 a.m.

  2. 12 noon

  3. 11.35 a.m.

  4. 11.25 a.m.

  5. None of these


Correct Option: D
Explanation:

The clock loses $5$ minutes per day
in 7 days, time lost $=5 \times 7=35mins$
actual time $=12'o clock$,
time shown $=11:25 a.m.$

A clock is set to show the correct time at 11:00 a.m. The clock gains 12 minutes in 12 hours. What will be the correct time when the clock indicates 5:30 p.m. the next day?

  1. 5.00 p.m.

  2. 5.10 p.m.

  3. 5.20 p.m.

  4. 6.00 p.m.

  5. 5.48 a.m.


Correct Option: A
Explanation:

The clock gains 12 mins in 12 hours,
It will gain 1 min in every 1 hour.
Difference in time the clock indicates=5:30 p.m.-11 a.m. (the next day)
=30.5 hours,
Time gained=30.5/1=30 mins.
Actual time=5 p.m.

There are two clocks on a wall, both set right at 10:00 a.m. One clock is losing 2 minutes per hour and the other clock is gaining 3 minutes per hour. If the clock which is losing 2 minutes per hour shows 3:00 p.m. the next day, what time does the clock gaining 3 minutes per hour show?

  1. 5.30 p.m.

  2. 4.00 p.m.

  3. 4.15 p.m.

  4. 5.00 p.m.

  5. None


Correct Option: A
Explanation:

In each hour, the time difference between the 2 clocks will increase by 5mins
time passed $=24+2+3=29hrs$ on clock 1
Real time on clock $1=4 p.m$
difference between 2 clocks=$5*30=150mins$,
time on clock $2=3hrs+2hrs+30mins$
$=5.30 p.m$

At what time, between twelve o'clock and one o'clock, will the hands of the clock overlap again?

  1. 12 hours $\displaystyle 50 \frac{2}{11}$ minutes

  2. 12 hours 45 minutes

  3. 12 hours 59 minutes

  4. Never happen

  5. None of these


Correct Option: D
Explanation:

At twelve o'clock, the 2 hands are overlapping. 
As the minutes pass, the minutes hand moves farther away from the hours hand.
Therefore, between 
twelve o'clock and 1 o'clock, the hands will not overlap again.

A watch showed five past five on Wednesday evening when the correct time was 5:00 p.m. It loses uniformly, and was 5 minutes slow after two days at 7:00 p.m. When did the watch show the correct time?

  1. Thursday 6:00 a.m.

  2. Thursday 6:00 p.m.

  3. Thursday 6:30 p.m.

  4. Thursday 5:00 a.m.

  5. None of these


Correct Option: B
Explanation:

Since the watch was 5 minutes fast on Wednesday evening, 5:00 p.m. and was 5 minutes slow after two days at 7:00 p.m., the correct time would be at the mid point of these 2 times.
Time difference=(24+24+2)50 hours,
So the right time will be 25 hours past 5 p.m. Wednesday,
I.e, 6 p.m. on Tuesday.

A clock gains 10 minutes in 2 hours. It is set right at 10:I0 a.m. When the clock shows 4:40 p.m. on the same day, what is the correct time?

  1. 4.54 p.m.

  2. 5.00 p.m.

  3. 5.10 p.m.

  4. 4.10 p.m.

  5. None of these


Correct Option: D
Explanation:

Let the hours passed be x,
time difference as per clock=5hrs and 30mins 
actual time=x*60+x*5=330,
x=5 hrs,
actual time=4:10

A  certain $12$-hour digital clock displays the hour and minute of a day. Due to a defect in the clock whenever the digit $1$ is supposed to be displayed it displays $7$. What fraction of the day will the clock show the correct time?

  1. $\displaystyle \frac {1} {2} $

  2. $\displaystyle \frac {5} {8} $

  3. $\displaystyle \frac {3} {4} $

  4. $\displaystyle \frac {5} {6} $


Correct Option: B
Explanation:

The clock will show 1 in an hour for 19 time for 11 hours it will show the incorrect time for $(19 \times 11)$ time. The last 12th hour will always show the in correct time so total in correct time.

$(19 \times 11 + 60)$ min = $269$ min

there are $24$ hours in a day to $ = 269 \times 2 = 538 $ min

$538$ min = $\displaystyle \frac {269} {30} = 9 $ hours

the fraction day when the clock shows the correct time is $\displaystyle = 1 - \frac {9} {24} $

                                                                                                 $\displaystyle = 1 - \frac {3} {8} = \frac {5} {8}$

There are two clocks, both set to show correct time at 9:00 a.m. One clock loses 1 minute every hour, and the other gains 1 minute every hour. By how many minutes do they differ at 10:00 p.m. on the same day?

  1. 24 minutes

  2. 30 minutes

  3. 28 minutes

  4. 26 minutes

  5. 13 minutes


Correct Option: D
Explanation:

After each hour, the difference between clocks will increase by 2 minutes.
At 10 p.m., hours passed=13,
Difference=13*2=26 minutes.

Imagine a clock where the hour hand makes only one revolution in 1 day (i.e., 24 hours) whereas the minute hand completes one revolution in 1 hour. What is the angle between the two hands at 14:50 hours as per this clock?

  1. 90$^o$

  2. 120$^o$

  3. 77.5$^o$

  4. 162.5$^o$

  5. None


Correct Option: C
Explanation:

14:50 in the current clock would be indicated by the hour hand a little before midway of 7 and 8 and minute hand would be on 10.

A clock strikes once at one o'clock, twice at two o'clock, thrice at three o'clock, and so on. How many times, in total, will it strike in 24 hours?

  1. 144

  2. 288

  3. 300

  4. 156

  5. 72


Correct Option: D
Explanation:

Clock strikes the same number of times as the hour that it is in, i.e, once at 1. 
The hours on the clock range from 1 to 12.
In a span of 24 hours, it will complete the cycle twice.
number of times it strikes=2(1+2+...12)
=156

How many times do the hands of a clock make an angle of 90$^o$ in 36 hours?

  1. 11

  2. 22

  3. 44

  4. 72

  5. 66


Correct Option: E
Explanation:

If you switch to a rotating coordinate system in which the hour hand stands still, then the minute hand makes only 11 revolutions, and so it is at right angles with the hour hand 22 times. In 36 hours, you get 322=66.

A clock runs 6 minutes slow per day. By what percentage is it running slow?

  1. 6

  2. 1/10

  3. 12/5

  4. 5/12

  5. None of these


Correct Option: D
Explanation:

$The\quad clock\quad is\quad running\quad 6\quad minutes\quad slow\quad in\quad 1\quad day,\ %\quad of\quad time\quad lost=\frac { 6 }{ 24*60 } *100=\frac { 5 }{ 12 }%$

What is the angle between the $2$ hands of the clock at $8:24$ pm?

  1. $\displaystyle 100^{\circ}$

  2. $\displaystyle 107^{\circ}$

  3. $\displaystyle 106^{\circ}$

  4. $\displaystyle 108^{\circ}$


Correct Option: D
Explanation:

Required angle = 240 - 24 $\displaystyle \times $ (11/2)
                        = 240 - 132 = $\displaystyle 108^{\circ}$

At what angle are the hands of a clock inclined at $30$ minutes past $6 $?

  1. $7\displaystyle\frac{1}{2}$

  2. $11\displaystyle\frac{1}{2}$

  3. $15$

  4. $23$


Correct Option: C
Explanation:

Angle between hands of clock $=\left| 30H- \displaystyle\frac { 11 }{ 2 } M \right| $
where $H \rightarrow $ Hour hand, $M \rightarrow $ Minute hand
$\therefore  \left| 30\times 6- \displaystyle\frac { 11 }{ 2 } \times 30 \right| =15$

There are two clocks on a wall, both set right at 10:00 a.m. on Sunday. Both the clocks lose 1 minute and 2 minute, respectively, every hour. Ifthe clock which loses 2 minutes every hour shows 8:00 p.m. on the following Tuesday, what time does the clock which loses 1 minute every hour show?

  1. 8:30 p.m.

  2. 9:00 p.m.

  3. 8:45 p.m.

  4. 9:30 p.m.

  5. None of these


Correct Option: B
Explanation:

Let the hours passed be x,
time shown on clock 1=8:00 p.m. tuesday (24+24+10 hrs)
60x-2x=58*60,
x=60hrs,
actual time=10:00 p.m.
time on clock 2=(60-1)*60=59hrs,
=9:00 p.m. tuesday.

A clock has numbers $1$ to $12$. If a clock has a shape of a circle, then the degree measure made by an arc between any two consecutive numbers of the clock is

  1. $60$

  2. $30$

  3. $45$

  4. $90$


Correct Option: B
Explanation:

$12\rightarrow \frac { 360 }{ 12 } 30$

From $6$ am to $6$ pm, the number of times the angle between the two hands of a clock is $\displaystyle { 180 }^{ o }$ is 

  1. $2$

  2. $11$

  3. $13$

  4. $14$


Correct Option: B
Explanation:

The two hands of a clock make $\displaystyle { 180 }^{ o }$ when they face each other in a straight line. 
This happens 11 times in 12 h. 
At 6 am and 6 pm, two hands form $\displaystyle { 180 }^{ o }$
Number of times they form $\displaystyle { 180 }^{ o }$ = 11 

A watch which gains uniformly was observed to be 5 minutes slow at 12 noon on a Sunday. On the subsequent Wednesday at 6:00 p.m., it was noticed that the watch was 5 minutes fast. When did the watch show the correct time?

  1. On Monday at 12 noon

  2. On Monday at 3:00 a.m,

  3. On Tuesday at 3:00 a.m.

  4. On Tuesday at 12 midnight

  5. None of these


Correct Option: C
Explanation:

Since the watch is  5 minutes slow at 12 noon on a Sunday and 5 minutes fast on the subsequent Wednesday at 6:00 p.m, it will show the right time at a time exactly mid way of theses 2 times.
hours passed=24+24+24+6=78hrs
mid way will be 39hrs after Sunday noon, which will be 3:00 a.m. tuesdsay.

A clock is set to show the correct time at 12:00 noon. Immediately, due to some mechanical defect, both the minute hand and the hour hand started moving in the reverse direction (anticlockwise direction). What is the correct time when this clock shows 8:25?

  1. $4:25$

  2. $3:25$

  3. $7:25$

  4. $7:35$

  5. $3:35$


Correct Option: E
Explanation:

When the hands are moving anticlockwise, we can assume that the time shown is the mirror image of actual time.
Assume that there is a line drawn between 12 and 6 on the clock, this can be a line of symmetry.
When we take the mirror image of this clock, the hands that are on the right side of this line will appear equidistant on the left side of the line and vice versa.
The time indicated is 8:25, the hour mid way after 8 and the minute hand on 5.
Its mirror image will become, the hour mid way before 4 and the minute hand on 7, i.e, 3:35.

The minute and hour hands of a clock overlap every 60 minutes of correct time. How much does the clock lose or gain in a day?

  1. $130 \displaystyle \frac{10}{11}$ minutes

  2. $58 \displaystyle \frac{6}{7}$ minutes

  3. $143 \displaystyle \frac{5}{11}$ minutes

  4. $139 \displaystyle \frac{4}{11}$ minutes

  5. None of these


Correct Option: A
Explanation:

In a correct clock, the minute hand gains 55 min. spaces over the hour hand in 60 minutes.

To be together again, the minute hand must gain 60 minutes over the hour hand.

55 minutes are gained in 60 min.

60 min. are gained in [(60/55) * 60] min = $65\frac { 5 }{ 11 } $min.

Therefore, loss in 60 minutes =  $65\frac { 5 }{ 11 } -60=5\frac { 5 }{ 11 } $ min.

Loss in 24 hours = $5\frac { 5 }{ 11 } *\frac { 24*60 }{ 60 } $ = $130\frac { 10 }{ 11 } $min.

Therefore, the clock loses $130\frac { 10 }{ 11 } $ minutes in 24 hours.

A clock loses 5 seconds every hour. If the clock is set on Sunday at 12 noon, then what is the correct time the following Saturday, if the clock shows 12, midnight (give answer to the nearest minute)?

  1. II:53 p.m. on Saturday

  2. 11:47 p.m. on Saturday

  3. 00: 13 a.m. on Sunday

  4. 11: 52 p.m. on Saturday

  5. None of these


Correct Option: C
Explanation:

Let the hours passed be $x$,
time shown on $clock 1=12:00 a.m$ saturday $(24*6+12hrs)$
$3600x-5x=156*60*60$,
$x=156.21hrs=156hrs$ and $13mins$
actual time $=12:13 a.m.$ saturday.

Write the following $24$ hr clock into $12$ hour clock.
$23:42$ .

  1. $9:42\ am$

  2. $11:42\ pm$

  3. $11:42\ am$

  4. $9:42\ pm$


Correct Option: B
Explanation:
$23:42$
Since hour is more than $12$ it is p.m.
$23-12=11$
Time is $11:42\ pm$

The minute hand of a clock overtakes the hour hand at intervals of 65 minutes. How much in a day does the clock gain or lose?

  1. Gains $\displaystyle 56 \frac{8}{77}$ minutes

  2. Loses $\displaystyle 32 \frac{8}{11}$ minutes

  3. Loses $\displaystyle 9 \frac{10}{143}$ minutes

  4. Gains $\displaystyle 10 \frac{9}{143}$ minutes

  5. Gains $\displaystyle 10 \frac{10}{143}$ minutes


Correct Option: E
Explanation:

In a correct clock, the minute hand gains 55 min. spaces over the hour hand in 60 minutes.

To be together again, the minute hand must gain 60 minutes over the hour hand.

55 minutes are gained in 60 min.

60 min. are gained in [(60/55) * 60] min = $65\dfrac { 5 }{ 11 } $min.

But they are together after 65 min.

Therefore, gain in 65 minutes =  $65\dfrac { 5 }{ 11 } -60=\dfrac { 5 }{ 11 } $ min.

Gain in 24 hours = $\dfrac { 5 }{ 11 } * \dfrac { 24*60 }{ 65 } $ = 1440/143 min.

Therefore, the clock gains $(10 + 10/143 )$ minutes in $24$ hours.

Two hours later would be as long until midnight. What time is it now?

  1. $18:30$

  2. $20:00$

  3. $21:00$

  4. $22:00$


Correct Option: D
Explanation:

$2$ hours before midnight means $22:00$.

Hence, option D is right answer.

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