1. What was day of the week on 21-September-1987?

a) Saturday

b) Sunday

c) Monday

d) Tuesday

Explanation: Formula : (Date + Month code + No.of years + No.of leap year + Century code)/7

$$\eqalign{ & = \frac{{21 + 6 + 87 + 21 + 0}}{7} = \frac{{135}}{7} \cr & = 2 \cr & = {\text{Monday}} \cr} $$

2. How many odd days are there from 13^{th} May, 2005 to 19^{th} August 2005 (both inclusive)?

a) 1

b) 2

c) 3

d) 4

Explanation: Here we have to count the number days from 13

^{th}May, 2005 to 18

^{rd}August 2005 ( both inclusive)

From 13

^{th}to 31

^{st}May = 19 days

In June = 30 days

In July = 31 days

From 1st to 19th April = 19 days

Total number of days = 19 + 30 + 31 + 19 = 99 days

The number of odd days are = 14 x 7 + 1 = 99

So there is 1 odd day in the given period

3. What is the year next to 1990 which will have the same calendar as that of the year 1990?

a) 1992

b) 2001

c) 1995

d) 1996

Explanation: For a year to have the same calendar with 1990 ,total odd days from 1990 should be 0. Take the year 1992 from the given choices.

Total odd days in the period 1990-1991 = 2 normal years

⇒ 2 x 1 = 2 odd daysTake the year 1995 from the given choices.

Number of odd days in the period 1990-1994 = 4 normal years + 1 leap year

⇒ 4 x 1 + 1 x 2 = 6 odd daysTake the year 1996 from the given choices.

Number of odd days in the period 1990-1995 = 5 normal years + 1 leap year

⇒ 5 x 1 + 1 x 2 = 7 odd days = 0 odd days

(As we can reduce multiples of 7 from odd days which will not change anything) Though number of odd days in the period 1990-1995 is 0, there is a catch here.

1990 is not a leap year whereas 1996 is a leap year.

Hence calendar for 1990 and 1996 will never be the same.Take the year 2001 from the given choices. Number of odd days in the period 1990-2000 = 8 normal years + 3 leap years

⇒ 8 x 1 + 3 x 2 = 14 odd days = 0 odd days

Also, both 1990 and 2001 are normal years.

Hence 1990 will have the same calendar as that of 2001

4. Find the number of odd days in 126 years.

a) 1

b) 2

c) 3

d) 4

Explanation: A period of 100 years has 5 odd days . In 26 years , 4 are leap, remaining are ordinary years

125 years = 100 years + 26 years

= 100 years + 6 leap years + 20 ordinary years

= 5 odd days + 12 odd days + 20 odd days

= 37 odd days = 5 x 7 +2 = 2 odd days

5. If the day before yesterday was Thursday, when will Sunday be?

a) Today

b) Tomorrow

c) Two days after today

d) Day after tomorrow

Explanation: Day before yesterday was Thursday

Yesterday was a Friday

Today is a Saturday

Tomorrow is a Sunday

6. Second & fourth Saturdays and every Sunday is a holiday. How many working days will be there in a month of 31 days beginning on a Friday ?

a) 24 days

b) 23 days

c) 22 days

d) 25 days

Explanation: Given that the month begins on a Friday and has 31 days

Sundays = 3

^{rd}, 10

^{th}, 17

^{th}, 24

^{th}, 31

^{st}

⇒ Total Sundays = 5

Every second & fourth Saturday is holiday. 2

^{nd}& 4

^{th}Saturday in every month = 2

Total days in the month = 31

Total working days = 31 - (5 + 2) = 24 days.

7. On 17^{th} March, 1997 Monday falls. What day of the week was it on 17^{th} March, 1996?

a) Monday

b) Tuesday

c) Saturday

d) Sunday

Explanation: The year 1996 is a leap year. So, it has 2 odd days. But 17th March comes after 29th February.

So, the day on 17

^{th}March, 1997 will be 1 day beyond the day on 17

^{th}March,1996.

Here 17

^{th}March, 1997 is Monday. So, 17

^{th}March, 1996 is Sunday.

8. Which year has 366 days?

a) 1900

b) 1200

c) 2500

d) 1700

Explanation: When a century year leaves a remainder 0, when divided by 400 then it is a leap year (366 days).

So, 1200 has 366 days.

9. What is 90 days from today?

a) 18^{th} April, Friday

b) 20^{th} April, Saturday

c) 21^{th} April, Sunday

d) 19^{th} April, Saturday

Explanation: Given Today is 20

^{th}January 2017, Sunday

In january, we have 31 days

February - 28 days (Non leap year)

March - 31 days

April - 30 days

⇒ Remaining days = 31 - 20 = 11 in Jan

11 in Jan + 28 in Feb + 31 in Mar = 11 + 28 + 31 = 70 days

More 20 days to complete 90 days ⇒ upto 20

^{th}April

Therefore, after 90 days from today i.e, 20

^{th}Jan 2017 is 20

^{th}Apr 2017.

Now, the day of the week will be

$$\frac{{90}}{7}$$ ⇒ Remainder '6'

As the day starts with '0' on sunday

6 ⇒ Saturday.

Required day is 20

^{th}April, Saturday.

10. On 24^{th} Nov, 2007 Thursday falls. What day of the week was it on 10^{th} Nov, 2006 ?

a) Wednesday

b) Tuesday

c) Friday

d) Thursday

Explanation: The year 2006 is an ordinary year. So, it has 1 odd day.

So, the day on 24

^{th}Nov, 2007 will be 1 day beyond the day on 24

th Nov, 2006.

But, 24

^{th}Nov, 2007 is Thursday.

24 - 10 = 14 days.

Therefore, 2 weeks ago it is same day.

10

^{th}Nov, 2006 is one day before 10

^{th}Nov, 2007 i.e. it is Wednesday.