Test: Clocks - Class 5 MCQ

Total number of strikings
= 2(1 + 2 + 3 +.....+ 12)

There are 8 intervals in 9 tinging 10 intervals in 11 tinging.
Time duration of 8 intervals = 9 seconds
∴ Required time = Duration of 10 intervals

Time interval from 9 am on Monday to 8 : 30 pm on Wednesday.
 = (24 × 2.5) − 0:30 hours  
= 60 − 0:30 hours
= 59 hours 30 minutes

Also 24 hours − 12 minutes
= 23 hours 48 minutes

= 30 minutes
Hence, the correct time is 30 minutes after 8:30 pm i.e., 9 pm

After 12 days, i.e., after 12 × 24 hours clock A will gain 48 minutes and will show 12 : 48 noon.
After 12 days, i.e., after 12 × 24 hours clock B will loose 16 minutes and will show 11 : 44 am
The two clocks will show the same time after time after 135 days.
The time difference has to be 12 hours between then = 720 minutes.
A will gain 540 minutes in 135 days.
B will loose 180 minutes in 135 days, total 720 minutes.
Further if we consider only time then the problem becomes simpler
Total difference of minutes between the times shown by the clocks after 36 hours

∴ 12 noon, after 135 days

The duration from 1 : 00 pm to 10 : 00 pm is 9 hours and during each of these 9 hours the hands of the clock are at right angles twice.
So, required number = 9 × 2 = 18

Since the time read by the lady was 57 minutes earlier than the correct time, so the minute hand is (60 - 57) = 3 minutes spaces behind the hour hand.
Now, at 5 o'clock, the minute hand is 25 minutes spaces behind the hour hand.
To be 3 minutes spaces behind, it must gain (25 - 3) = 22 minutes spaces.
55 minutes spaces are gained in 60 minutes.
22 minutes spaces are gained in = 24 minutes
Hence, the correct time was 24 minutes past 5.

Time from 1 pm on Wednesday to 1 pm on Thursday = 48 hours
So, the watch gains (1 + 2) minute or 3 minutes in 48 hours.
Now, 3 minutes are gained in 48 hours
So, 1 minute is gained in (48/3) = 16 hours.
Thus, the watch showed the correct time 16 hours after 1 pm on Tuesday, i.e., 5 am on Wednesday.

Time gained in 1 hour = 6 minutes
Time gained in 6 hours = (6 × 6) minutes = 36 minutes
After 6 hours, the correct time is 11 : 00 am and the watch will show 11 : 36 am.

One clock show 10 pm, on 21^st January 2010
One clock gains = 2 minutes
Other clock loses = 5 minutes
Time period between 10 pm and 4 pm = 18 hours
∴ Required difference
= (2 × 18 + 5 × 18 ) minutes
= 126 minutes

Number of rounds completed by the minute hand in 3 days 5 hours
= (3 × 24 + 5) = 77 = (3 × 24 + 5) = 77
Number of rounds completed by the hour hand in 3 days 5 hours

∴ Difference between the distance traversed

Time from 12 noon to 9 : 38 A.M.
= 12 hours + 9 hours 38 minutes
= 21 hours 38 minutes

Angle traced by the hour hand in 12 hours = 360°
Angle traced by the minute hand in

Number of rotation
= 72/12
= 6

The watch loses 1/2 hour each hour. So, it must have take 8 hours to show 4 pm from 12 noon.
Thus, it stopped at 8 pm.
So, the correct time is 5 hours ahead of 8 pm, i,e., 1 am.

Angle traced by the minute hand in 2 hours 20 minutes,i.e.,

At 3 o'clock, the minute hand is 15 minutes spaces behind the hour hand.
Thus, the minute hand has to gain (15 + 18) = 33-minute spaces
55 minutes are gained in 60 minutes.
33 minutes are gained in 
∴ The hands will be 18 minutes spaces apart at 3 : 36 pm.

Angle traced by the minute hand in 5 minutes.

In 12 hours, the hands coincide or are in opposite direction 22 times.
∴ In 24 hours, the hands coincide or are in opposite direction 44 times a day.

The hands of a clock coincide 11 times in every 12 hours (Since between 11 and 1, they coincide only once, i.e., at 12 o'clock).
AM
12:00
1:05
2:11
3:16
4:22
5:27
6:33
7:38
8:44
9:49
10:55
PM
12:00
1:05
2:11
3:16
4:22
5:27
6:33
7:38
8:44
9:49
10:55
The hands overlap about every 65 minutes, not every 60 minutes.
∴ The hands coincide 22 times in a day.

The hands of a clock point in opposite directions (in the same straight line) 11 times in every 12 hours. (Because between 5 and 7 they point in opposite directions at 6 o'clcok only).
So, in a day, the hands point in the opposite directions 22 times.

In 12 hours, they are at right angles 22 times.
∴ In 24 hours, they are at right angles 44 times.