3rd Class Mental Ability Calendar Time, Days and Dates & Possible Combinations

Time, Days and Dates & Possible Combinations

OBJECTIVE

·         Students will get familiarity with the days of the week and months of the year.

·         They will learn reading calendar to find a particular day and date.

·         Students will ha able to find the number of possible combination in a given situation and calculate probabilities involved with them.

TIME

Time is measured with the help of a clock or a watch. A clock has two hands.

·         The shorter hand is called the Hour Hand.

·         The longer hand is called the Minute Hand.

·         The face of the clock is divided in 12 equal divisions.

·         The hour hand takes 12 hour to complete 1 round. It moves round the clock twice a day.

·         The minute hand takes 1 hour to complete one round. In 1 round, minute hand moves through 60 small divisions, each of which is equal to 1 minute.

·         On the clock, there are 5 minutes between the two consecutive numbers.

·         The minute hand moves 24 times round the clock in one day.

DAYS

The duration of 24 hours (from one mid-night to the next mid-night) is called 1 day.

1 day = 24 hours

Days of a Week

There are 7 days in a week.

The names of the seven days of the week in order are:

Yesterday.         Today.         Tomorrow

MONTHS

Some months have 30 days and some have 31 days, except February, which has 28 days. But in a leap year, the month February has 29 days.

Example - 1

Sita remembers that her brother Anuj's birthday was after 15th but before 20th September, while her mother remembers that Anuj's birthday was after 17th but before 19th September. On which date of September was Anuj's birthday?

(a) 16th                         (b) 18th         

(c) 19th                         (d) 20th

Ans. (b)

Explanation:

According to Sita Anuj's birthday was: 16, 17, \[\], 19

According to her mother Anuj's birhtday was: 18

According to both common days is 18th September.

Hence, Anuj's birth was on 18th September.

Example - 2

If 22nd August is Sunday, What day was on 22 days before?

(a) Sunday                     (b) Monday    

(c) Friday                       (d) Saturday

Ans. (d)

Explanation:

Difference of No. of days = 22

No. of odd days =1

[Because 22/7 =3+1]

1 day before Sunday is Saturday.

Hence, it will be Saturday before 22 days.

Example - 3

What will be the time 3 hours after 10 a.m.?

(a) 1:00 a.m.                  (b) 1:00 p.m.    

(c) 12'o clock                  (d) 2:00 p.m.

Ans. (b)

1: 00 pm time will be 3 hours after 10:00 am.

Example - 4

What is the time taken by a minute hand to move from one number to the next number?

(a) 10 minutes                (b) 1 minutes   

(c) 5 minutes                  (d) 2 minutes

Ans. (c)

5 minutes time is taken by a minute hand to move from one number to the next number.

Possibility

Possibility is a thing that may be chosen or done out of several possible alternatives.

Combination

A combination is a selection of all or part of objects, without regard to the order in which objects are selected.

For example, suppose we have a set of three letters: A, B, and C. we might ask how many ways we can select 2 letters from that set. Each possible selection would be an example of a combination. The complete list of possible selections would be: AB and BC.

Example - 5

How many possible combination of 1 man and 1 woman can be formed from 3 men and 3 women?

(a) 12                            (b) 15              

(c) 9                              (d) 18

Ans. (c)

Explanation:

Men \[\left( {{M}_{1}},\text{ }{{M}_{2}},\text{ }{{M}_{3}} \right)\]and Women \[\left( {{W}_{1}},\text{ }{{W}_{2}},\text{ }{{W}_{3}} \right)\]

Possible combinations:

\[({{M}_{1}}{{W}_{1}}),({{M}_{1}}{{W}_{2}}),({{M}_{1}}{{W}_{3}}),({{M}_{2}}{{W}_{1}}),({{M}_{2}}{{W}_{2}}),\]

 \[({{M}_{2}}{{W}_{3}}),({{M}_{3}}{{W}_{1}}),({{M}_{3}}{{W}_{2}}),({{M}_{3}}{{W}_{3}}).\]