Aptitude - Clock
1.
At what angle the hands of a clock are inclined at 15 minutes past 5 ?
Answer
Angle traced by hour hand in 12 hours = 360°
∴ Angle traced by hour hand in 5 1560 hrs i.e. 214 hrs =
360°12 x 214 
= 157.5°
Angle traced by hour hand in 60 min. = 360°
∴ Angle traced by hour hand in 15 min. = 360°60 x 15 = 90°
Required angle = 157.5° − 90° = 67.5°
Answer :
Option CExplanation :
Angle traced by hour hand in 12 hours = 360°
∴ Angle traced by hour hand in 5 1560 hrs i.e. 214 hrs =
360°12 x 214 = 157.5°Angle traced by hour hand in 60 min. = 360°
∴ Angle traced by hour hand in 15 min. =
360°60 x 15 = 90° Required angle = 157.5° − 90° = 67.5°
2.
How many times are the hands of a clock at right angle in a day ?
Answer
In 12 hours, they are at right angles 22 times.
∴ In 24 hours, they are at right angles 44 times.
Answer :
Option CExplanation :
In 12 hours, they are at right angles 22 times.
∴ In 24 hours, they are at right angles 44 times.
3.
A clock is started at noon. By 10 minutes past 5, the hour hand has turned through :
Answer
Angle traced by hour hand in 12 hrs = 360°.
Angle traced by hour hand in 5 hrs 10 min. i.e., 360°12 x 316 = 155°
Answer :
Option CExplanation :
Angle traced by hour hand in 12 hrs = 360°.
Angle traced by hour hand in 5 hrs 10 min. i.e.,
31 6
hrs = 360°12 x 316 = 155° 4.
At what time between 9 and 10 o'clock will the hands of a watch be together ?
Answer
To be together between 9 and 10 o'clock, the minute hand has to gain 45 min. spaces.
55 min. spaces are gained in 60 min.
∴ 45 min. spaces are gained in 6055 x 45 min or 49 111 min.
∴ The hands are together at 491 11 min. past 9
Answer :
Option CExplanation :
To be together between 9 and 10 o'clock, the minute hand has to gain 45 min. spaces.
55 min. spaces are gained in 60 min.
∴ 45 min. spaces are gained in
6055 x 45 min or 49 111 min.∴ The hands are together at 491 11 min. past 9
5.
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 ?
Answer
Angle traced by hour hand in 12 hours = 360°
∴ Angle traced by hour hand in 6 hours = 360°12 x 6 = 180°
Answer :
Option DExplanation :
Angle traced by hour hand in 12 hours = 360°
∴ Angle traced by hour hand in 6 hours =
360°12 x 6 = 180° Jump to page number :