Clocks and Time  Quantitative Aptitude Test | RRB Group D

  • Clocks and Time
  • 1. How many times do the hands of a clock coincide in a day? 
   A.) 20
   B.) 21
   C.) 22
   D.) 23

Answer: Option 'C'

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). 
==> The hands coincide 22 times in a day.

  • 2. How many times are the hands of a clock at right angles in a day? 
   A.) 22
   B.) 44
   C.) 38
   D.) 48

Answer: Option 'B'

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

  • 3. How much does a watch lose per day, if its hands coincide every 64 minutes? 
   A.) 32 8/11min
   B.) 36 5/11min
   C.) 90min
   D.) 96min

Answer: Option 'A'

55 min. spaces are covered in 60 min.
60 min spaces are covered in (60/55 × 60)min = 65 5/11 min
Loss in 64 min = ( 65 5/11- 64 ) = 16/11 min
Loss in 24 hrs = ( 16/11 × 1/64 × 24 × 60 ) min
= 32 8/11 min

  • 4. How many times in a day the hands of a clock are straight?
   A.) 22
   B.) 21
   C.) 43
   D.) 44

Answer: Option 'D'

In 12 hours, the hands coincide or are in oppesite direction 22 times. 
In 24 hours, they are at right angles 22 times.

  • 5. At what time between 4 & 5 will the hands of a watch point in opposite directions?
   A.) 43 min past 4
   B.) 42 5/11 min past 4
   C.) 50 4/11 min past 4
   D.) 40 min past 4

Answer: Option 'C'

At 4 o'clock, the hands of the watch are 20 min. spaces apart. 
To be in opposite directions, they must be 30min. spaces apart. 
Minute hand will have to gain 5 min. spaces. 
55min spaces are gained in 60 min. 
5 min. spaces are gained in (60/55 × 50) min. or 54 6/11 min.
Required time = 54 6/11 min. past 4.

  • 6. At what time between 9&10 will the hands of a watch be together? 
   A.) 45 min past 9
   B.) 49 1/11 min past 9
   C.) 48 min past 9
   D.) 47 min past 9

Answer: Option 'B'

To be together between 9 and 10 O'clock, the minute hand has to gain 45min. 
spaces 55min. spaces are gained in 60min.
45min.spaces are gained in (60/55 × 45) min. or 49 1/11 min. 
The hands are together at 49 1/11 min. past 9.

  • 7. At what time between 5.30 & 6 will the hands of a watch be at right angle? 
   A.) 43 7/11 min past 5
   B.) 41 2/11 min past 5
   C.) 42 min past 5
   D.) 44 1/11 min past 5

Answer: Option 'A'

At 5 o'clock, the hands are 25 min. spaces apart. 
To be at right angles and that too between 5.30 and 6, the minute hand has to 
gain 55min. spaces are gained in 60min.
4min. spaces are gained in (60/55 × 40) min. = 43 7/11min. 
Required time = 43 7/11min.past 5.

  • 8. At what time between 7 & 8 o'clock will the hands of a watch be in the straight line but no together? 
   A.) 5 3/11 min past 7
   B.) 5 5/11 min past 7
   C.) 5 3/11 min past 7
   D.) 43min past 7

Answer: Option 'B'

When the hands of the clock are in the same straight line but not 
togerther, they are 30 minute spaces apart.
At 7 o'clock, they are 25min. spaces apart. 
Minute hand will have to gain only 5 min. 
space 55 min. spaces are gained in 60min.
5min. spaces are gained in ( 60/55 × 5) min = 5 5/11 min. 
Required time = 5 5/11 min. past 7.

  • 9. An accurate clock shows 8 o'clock in the morning. Through how many degrees will the hour hand rotate  when the clock shows 2 o'clock in the afternoon? 
   A.) 144º
   B.) 150º
   C.) 168º
   D.) 180º

Answer: Option 'D'

Angle traced by the hour hand in 6 hours = ( 360/12 × 11/3 )degrees 
=180º

  • 10. How much watch gain or lose per day, If its hands coincide every 64 min’s? 
   A.) Gain 92 min
   B.) Lose 9 min
   C.) Lose 34 5/11 min
   D.) Lose 32 8/11 min

Answer: Option 'D'

55 min. spaces are covered in 60 min. 
60 min. spaces are covered in (60/55 × 60) min = 65 5/11min 
Loss in 64min = (65 5/11 - 64) = 16/11 min 
Loss in 24 hrs= (16/11 × 1/64 × 24 × 60 ) min = 32 8/11 min. 



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