Clocks and Calendars


  1. The last day of a century cannot be ?











  1. View Hint View Answer Discuss in Forum

    100 yr have 5 odd days.
    ∴ Last day of 1st century of is Friday.

    200 yr have (5 x 2) = 1 week + 3 odd day = 3 odd day
    ∴ Last day of 2nd century of Wednesday,

    300 yr have (5 x 3) = 2 week + 1 odd day = 1 odd day
    ∴ Last day of 3rd century is Monday.

    400 yr have 0 odd day.
    ∴ Last day of 4th century is Sunday.

    Correct Option: A

    100 yr have 5 odd days.
    ∴ Last day of 1st century of is Friday.

    200 yr have (5 x 2) = 1 week + 3 odd day = 3 odd day
    ∴ Last day of 2nd century of Wednesday,

    300 yr have (5 x 3) = 2 week + 1 odd day = 1 odd day
    ∴ Last day of 3rd century is Monday.

    400 yr have 0 odd day.
    ∴ Last day of 4th century is Sunday.

    This cycle is repeated.
    ∴ Last day of a century cannot be Tuesday of Thursday of Saturday.


  1. On what day dates March, 2005 did Saturday fall?











  1. View Hint View Answer Discuss in Forum

    First, we find out the day on 1.03.2005. Period upto 1.3.2005.
    = (2004 yr + Period from 1.1.2005 to 1.3.2005)
    ∴ Odd day in 1600 yr = 0
    Odd day in 400 yr = 0
    4 yr = (1 leap year + 3 ordinary years)
    = (1 x 2 + 3 x 1) = 5 odd days

    Correct Option: B

    First, we find out the day on 1.03.2005. Period upto 1.3.2005.
    = (2004 yr + Period from 1.1.2005 to 1.3.2005)
    ∴ Odd day in 1600 yr = 0
    Odd day in 400 yr = 0
    4 yr = (1 leap year + 3 ordinary years)
    = (1 x 2 + 3 x 1) = 5 odd days

    Number of days between 1.1.2005 to 1.3.2005,
    = January + February + March
    = 31 + 28 + 1
    = 60 days = (8 weeks + 4 days)
    = 4 odd days

    Total number of odd days
    = (0 + 0 + 5 + 4) = 9
    = 1 weak + 2 odd days
    ∴ 1.3. 2005 was Tuesday.

    So, Saturday will fall on 5.3.2005.
    Hence, Saturday lies on 5th, 12th, 19th, and 26th of March 2005.



  1. What was the day of the week on 17th August, 2010 ?











  1. View Hint View Answer Discuss in Forum

    Period upto 17th August, 2010 = (2009 yr + Period from 1.1.2010 to 17.8. 2010)

    Counting of odd days
    Odd day in 1600 yr = 0
    Odd days in 400 yr = 0
    9 yr = (2 leap years + 7 ordinary years)
    = ( 2 x 2 + 7 x 1) = 1 week + 4 days = 4 odd days

    Number of days between 1.1.2010 to 17.8.2010
    January + February + March + April + May + June + July + August.
    = (31 + 28 + 31 + 30 + 31 + 30 + 31 + 17) days
    = 229 days = 32 weeks + 5 odd days

    Correct Option: C

    Period upto 17th August, 2010 = (2009 yr + Period from 1.1.2010 to 17.8. 2010)

    Counting of odd days
    Odd day in 1600 yr = 0
    Odd days in 400 yr = 0
    9 yr = (2 leap years + 7 ordinary years)
    = ( 2 x 2 + 7 x 1) = 1 week + 4 days = 4 odd days

    Number of days between 1.1.2010 to 17.8.2010
    January + February + March + April + May + June + July + August.
    = (31 + 28 + 31 + 30 + 31 + 30 + 31 + 17) days
    = 229 days = 32 weeks + 5 odd days

    Total number of odd days = (0 + 0 + 4 + 5 ) days
    = 9 days = 1 week + 2 odd days
    Hence, the required day is Tuesday.


  1. What was the day of the week on 5th June, 2002 ?











  1. View Hint View Answer Discuss in Forum

    Period upto 5th June, 2002 = (2001 yr + Period from 1.1.2002 to 5.6.2002)
    ∴ Odd days in 1600 yr = 0
    Odd days in 400 yr = 0
    Odd days in 1 ordinary year = 1
    Odd days in 2001 year = (0 + 0 + 1) = 1

    Number of days from 1.1.2002 to 5.6.2002
    January + February + March + April + May + June
    = 31 + 28 + 31 + 30 + 31 + 5
    = 156 days = 22 weeks + 2 days
    = 2 odd days

    Correct Option: A

    Period upto 5th June, 2002 = (2001 yr + Period from 1.1.2002 to 5.6.2002)
    ∴ Odd days in 1600 yr = 0
    Odd days in 400 yr = 0
    Odd days in 1 ordinary year = 1
    Odd days in 2001 year = (0 + 0 + 1) = 1

    Number of days from 1.1.2002 to 5.6.2002
    January + February + March + April + May + June
    = 31 + 28 + 31 + 30 + 31 + 5
    = 156 days = 22 weeks + 2 days
    = 2 odd days

    ∴ Total number of odd days = (1 + 2) = 3
    ∴ The required day is Wednesday.



  1. Find at what time between 8 and 9 O’clock will the hands of a clock be in the same straight line but not together?









  1. View Hint View Answer Discuss in Forum

    Here, H = 8 > 6.
    We know that ,

    ∴ (5H - 30)12= (5 x 8 - 30) 12
    1111

    Correct Option: C

    Here, H = 8 > 6.
    We know that ,

    ∴ (5H - 30)12= (5 x 8 - 30) 12
    1111

    = 120= 10 10
    1111
    So, the hands will be in the same straight line but not together at
    10
    10
    minutes past 8 O’clock.
    11