## mathslover 3 years ago Calendar concept ..

1. mathslover

@annas and @angela210793

2. mathslover

for example : november 9 , 1991

3. mathslover

1990 = 1600 + 300 + 0

4. mathslover

odd days in 1600 = 0 and in 300 = 1 .. hence we get total odd days in 1900 = 1

5. mathslover

now calculate the total number of days from 1.1.1991 to 9.11.1991

6. mathslover

since 1991 is not a leap year hence we have days in february = 28 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 9 = 313 divide that by 7 we get remainder = 5 hence total number of odd days = 1 + 5 = 6

7. mathslover

Monday Tuesday Wednesday Thursday Friday Saturday Sunday 1 2 3 4 5 6 7 total number of odd days = 6 hence on 9 november 1991 it was saturday

8. mathslover

@annas right?

9. angela210793

Very niice :D

10. mathslover

yes it is a very nice process also

11. mathslover

useful process

12. annas

O.o i m shocked ... but awesome

13. mathslover

:) thanks

14. annas

we can make a computer program on that

15. annas

logic

16. mathslover

yes .. can u?

17. annas

i can try , i have to make an algorithm on that first. i'll try as soon as my website work is done

18. mathslover

oh k

19. nitz

but i didnt get.......

20. mathslover

what is ur date of birth .. i will take urs as an example

21. nitz

15 july 1992

22. mathslover

ok so first of all : 1992 = 1600 + 300 + 2 right?

23. nitz

wait always we have to break into 1600 +........so on

24. mathslover

yes it becomes easy

25. mathslover

wait we will take 1991 here: 1991 = 1600+300+1 1600 = 0 odd days 300 = 1 odd day 1 = 1 odd day now calculate the number of days from 1.1.1992 to 15.07.1992 31+29+31+30+31+30+15 = 197 divide 197 by 7 remainder = 1 hence total number of odd days = 1 + 1 + 1 = 3

26. mathslover

hence the day on 15 july 1992 = wednesday

27. mathslover

got it ? @nitz

28. nitz

wait...

29. nitz

300........1 odd day??

30. mathslover

yes

31. mathslover

Number of odd days in 300 years = (5 x 3) =15/7 = remainder = 1 odd day.

32. mathslover

we can write 300 = (100)*3 number of odd days in 100 = 5 and hence in 300 it will be 5*3 = 15 / 7 remainder = 1

33. mathslover

got it?

34. mathslover

100 years = 76 ordinary years + 24 leap years = (76 x 1 + 24 x 2) odd days = 124 odd days. = (17 weeks + days) 5 odd days. Number of odd days in 100 years = 5.

35. nitz

leave it ........i am getting confused anyways thank you,,,,,,,

36. mathslover
37. mathslover

this is a confusing topic no problem

38. nitz

i learnt some simple tricks like 85^2,125^2......

39. mathslover

85^2 = (90-5)^2 = 8100+25-900 = 8125-900 = 7225

40. mathslover

well wait lemme show u the shortcut one also

41. nitz

\[85^{2}=?\] firstly mutiply last two :5*5=25 then multiply first digit that is 8*9=72 so 7225

42. mathslover

:D right

43. nitz

i have multiplied first digit with a digit exceeding it....8*9=72

44. mathslover

125^2 = 5^2 12*13=156 15625 = 125^2

45. nitz

ya....

46. nitz

even for 11.... say 49*11 we have 9 as it is 4+9=13 i carry off and4+1=5 so 539

47. lgbasallote

...i dont get it...

48. mathslover

should i give u another example?

49. mathslover

@lgbasallote so lemme take this as an example : what is the day on 06-8-2012 ? ok?

50. lgbasallote

yeah sure

51. mathslover

ok so 2011 = 1600 + 300 + 111 right ?

52. lgbasallote

but you're looking for 2012...

53. mathslover

yes but we will calculate odd days in 2011 years and then from 01-08-2012 to 06-08-2012

54. mathslover

since 2012 is not a complete year hence we are taking 2011 there. . ok?

55. lgbasallote

go on

56. mathslover

wait i am making it soo long sorry

57. mathslover

ok so .. 2011 = 1600 + 300 + 100+10+1 odd days in 1600 = 0 , in 300 = 1 and in 111= 5 now : count the total number of days from 1.1.2012 to 6.8.2012 : 31+29+31+30+31+30+31+6 = 219 divide 219 by 7 : we get remainder as 2 hence total number of odd days : 5 + 1 + 2 = 6 + 2 = 8 now : 8 days / 7 = remainder = 1 hence finally 1 odd day that denotes that the day on 06.08.2012 is monday monday

58. mathslover

Made it short :D .. well do you know the exact meaning of odd days?

59. mathslover

well do you know understand what this concept is? any more questions

60. lgbasallote

what do you mean 0 odd days in 1600; 1 in 300 and 5 in 111

61. mathslover

hint : 1 ordinary year = 52 weeks + 1 day hence that 1 day is odd day =1

62. Yahoo!

@mathslover can u expl this to me

63. mathslover

No problem what is ur date of birth ?

64. mathslover

ok . so 1995 = 1600 + 300 + 5 right?

65. mathslover

oops wait it is : 1995 = 1600 + 300 + 95 right?

66. Yahoo!

it is 1996

67. mathslover

1996 is not a full year .. hence we will take 1995 there .. ok?

68. Yahoo!

wat do u mean by full year

69. Yahoo!

wat do u mean by full year

70. Yahoo!

@mathslover

71. mathslover

full year means that : 365 days in 1996 you dont have 365 days as ur birthday is on 11 - 03 .. got it?

72. Yahoo!

ok

73. mathslover

now no. of odd days in 1600 =0 in 300 = 1 and in 95 =6 count days from 1.1.1996 to 11.03.1996 31+29+11 = 71 71/7 = remainder = 1 total odd days = 6+1+1 = 8 hence on 11.03.1996 it was monday

74. mathslover

95/4 = 23 .. hence 95 years = 23 leap years + 72 ordinary years odd days in 95 years = 23*2 + 72*1=46+72 = 118 118/7 = remainder = 6

75. mathslover

got it @Yahoo! ?

76. Yahoo!

u r correct....

77. mathslover

thanks

78. Yahoo!

@mathslover Any video on this topic

79. mathslover

well not yet but lemme check it

80. mathslover

sorry no .. @Yahoo! http://www.indiabix.com/aptitude/calendar/ prefer this

81. mathslover

good question : for example : 1 ordinary year has 365 days there are totally 52 weeks and 1 day .. that 1 day is called odd day

82. RyanL.

Can you explain why the mayan calendar says the world is going to end this year?

83. mathslover

well that are superstitions , only mayan calendar can explain sorry

84. ParthKohli

@RyanL. It has been assumed that the world will end just because 2012 is the last year mentioned in Mayan Calendar.