Sample Material of Online Coaching For SSC CGL (Tier - 2) - Clocks and Calendar
Sample Material SSC CGL TIER-2 Online Coaching
Numerical Aptitude (Chapter: Clocks and Calendar)
Clock
A clock has 2 hands, the smaller one is called the hour hand or short hand
while the larger one is called the minute hand or long hand.
The face of a clock is a circle which subtends an angle of 360° at the centre.
Some Important Points
In every hour
1.
- Both the hands coincide once. At this point the angle between them is 0°.
- The hands are straight (point in opposite directions) once. At this point the angles between them are 180°.
- The hands are twice perpendicular to each other. At this point the angle between them is 90°.
2.
-
In 60 min the minute hand covers 360°. Thus, in 1 min the minute hand covers (360)°=6° 60 -
In 12 h the hour hand covers 360°. Thus, in 1 min the hour hand covers ( 360 )°=1° 12x60 2 Thus, in 1 minute, the minute hand gains (6-1)°=11/2° than the hour hand. 2
3.
- When the two hands are at right angles, they are 15min spaces apart.
- When the two hands are in opposite directions, they are 30 min spaces apart.
- In 60 min the minute hand gains 55 min on the hour hand.
- The minute hand moves 12 times as fast as the hour hand.
Calendar
1. Odd Days: The number of days more than the complete weeks for a
given period called odd days.
2. Ordinary Year: An ordinary year has 365 days and an ordinary year is
not a leap year.
3. Leap Year:
- Any year (except a century) which is divisible by 4 is a leap year.
- However, every 4th century is a leap year, ie, a century is a leap year when it is divisible by 400.
- A leap year has 366 days.
Examples of Leap Year 1924, 1908, 1944, 2008, 1684, etc., are all leap years.
400, 800, 1200, 1600, 2000, etc., are all leap years.
:: Home Assignment for Practice ::
1. If the hands of a clock coincide every 64 min (true time) in 24 h. How much a day does the clock gain?
2. If the hands of a clock coincide every 66 min (true time) in 24 h, how much a day does the clock loose?
3. At what time between 5 and 5 : 30 are the hands of a clock 5 min apart ?
4. A clock is set right at 10 am. The clock gains 10 min in a day. What will be the true time when the watch indicates 3 pm the next day ?
(a) 12 min past 2 pm
(b) 45 min past 2 pm
(c) 48 min past 2 pm
(d) 30 min past 2 pm
5. A clock is set to show the correct time at 7 am. Monday. The clock loses 15 min in 24 h. What will be the true time when the clock indicates 6 am on the following Friday?
(a) 6 : 15 am Friday
(b) 6 : 30 am Friday
(c) 7 am Friday
(d) 7 : 15 am Friday