Birthday Puzzle
ideaquest
his/her coming birthdays as such:
1st Birthday on a Monday
2nd Birthday on a Tuesday
3rd Birthday on a Wednesday
4th Birthday on a Thursday
5th Birthday on a Friday
6th Birthday on a Saturday
7th Birthday on a Sunday
8th Birthday back on a Monday
What year is this child born?
What is the earliest possible birthday? (month, day)
Ted S.
news:a1lt9u$ihu$1...@newton.pacific.net.sg:
[The original problem is saved as spoiler space.]
In a normal year, there are 52wks + 1 day. In a leap year, there are
52 wks+2 days. Since there are seven consecutive years where there are
just 365 days, those must be 2097-2103. So, the child's 8th birthday
will be in 2004, but before February 29.
The child was born in 2096, and since the child's 1st birthday is a
Monday, the child, having been born before 29 February, must have been
born on a Saturday. There are eight such dates:
7 January 2096
14 January 2096
21 January 2096
28 January 2096
4 February 2096
11 February 2096
18 February 2096
25 February 2096
--
Ted S.: change .spam to .net to reply by e-mail
Bart Simpson, interviewing his father: What religion are you?
Homer: You know, the one with all the well-meaning rules that don't
work out in real life. Uh, Christianity.
Mark Brader
>
>
>
>
>
>
>
>
>
>
> > A child who is born in this century, will have the priviledge of
> > celebrating his/her coming birthdays as such:
> >
> > 1st Birthday on a Monday
> > 2nd Birthday on a Tuesday
> > 3rd Birthday on a Wednesday
> > 4th Birthday on a Thursday
> > 5th Birthday on a Friday
> > 6th Birthday on a Saturday
> > 7th Birthday on a Sunday
> > 8th Birthday back on a Monday
> >
> > What year is this child born?
> > What is the earliest possible birthday? (month, day)
> In a normal year, there are 52wks + 1 day. In a leap year, there are
> 52 wks+2 days. Since there are seven consecutive years where there are
> just 365 days, those must be 2097-2103.
Wrong -- because they aren't calendar years.
> So, the child's 8th birthday
> will be in 2004, but before February 29.
>
> The child was born in 2096, and since the child's 1st birthday is a
> Monday, the child, having been born before 29 February, must have been
> born on a Saturday. There are eight such dates:
>
> 7 January 2096
> 14 January 2096
> 21 January 2096
> 28 January 2096
> 4 February 2096
> 11 February 2096
> 18 February 2096
> 25 February 2096
These are the *last* dates that meet the conditions. The child could
be born on any Saturday from March 2095 to February 2096 inclusive --
so the earliest possible date is March 5, 2095.
--
Mark Brader "To err is human, but to really mess things up
Toronto you need a timetable planner!"
m...@vex.net -- Richard Porter
My text in this article is in the public domain.
Terry O'Brien
"Ted S." <fe...@bestweb.spam> wrote in message
news:Xns9193A1F3927...@127.0.0.1...
> Somebody claiming to be "ideaquest" <idea...@yahoo.com> wrote in
> news:a1lt9u$ihu$1...@newton.pacific.net.sg:
>
> [The original problem is saved as spoiler space.]
>
>
>
>
>
>
>
>
>
>
> > A child who is born in this century, will have the priviledge of
> > celebrating his/her coming birthdays as such:
> >
> > 1st Birthday on a Monday
> > 2nd Birthday on a Tuesday
> > 3rd Birthday on a Wednesday
> > 4th Birthday on a Thursday
> > 5th Birthday on a Friday
> > 6th Birthday on a Saturday
> > 7th Birthday on a Sunday
> > 8th Birthday back on a Monday
> >
> > What year is this child born?
> > What is the earliest possible birthday? (month, day)
>
> In a normal year, there are 52wks + 1 day. In a leap year, there are
> 52 wks+2 days. Since there are seven consecutive years where there are
> just 365 days, those must be 2097-2103. So, the child's 8th birthday
> will be in 2004, but before February 29.
In the eight year period from March 1st 2096 to February 28th 2104 there
will be no leap years. Any child whose first birthday falls on a Monday in
the first year (1st March 2096 to 28th Feb 2097) will have subsequent
birthday dates as specified.
I.e. the child can may have been born on any Saturday between 1st March 2095
to 28th Feb 2096.
Hence there is no unique year (in the 1st Jan - 31st Dec sense).
The earliest possible birth date is Saturday 5th March 2095.
David A Karr
Suppose a child born in this century celebrates her first eight
birthday anniversaries on the following days:
1st: Friday
2nd: Saturday
3rd: Sunday
4th: Monday
5th: Tuesday
6th: Wednesday
7th: Thursday
8th: Friday again
What's the latest possible date on which this child might be born?
While at first glance this may look just like the previous puzzle
except that it starts with a Friday rather than a Monday, the fact
that we might agree on the answer to the Monday puzzle doesn't
imply we'll necessarily agree on the answer to this one.
--
David A. Karr "Groups of guitars are on the way out, Mr. Epstein."
ka...@shore.net --Decca executive Dick Rowe, 1962
Virgil
ka...@shell2.shore.net (David A Karr) wrote:
> A minor question of trivia.
>
> Suppose a child born in this century celebrates her first eight
> birthday anniversaries on the following days:
>
> 1st: Friday
> 2nd: Saturday
> 3rd: Sunday
> 4th: Monday
> 5th: Tuesday
> 6th: Wednesday
> 7th: Thursday
> 8th: Friday again
>
> What's the latest possible date on which this child might be born?
>
> While at first glance this may look just like the previous puzzle
> except that it starts with a Friday rather than a Monday, the fact
> that we might agree on the answer to the Monday puzzle doesn't
> imply we'll necessarily agree on the answer to this one.
I will guess that Wednesday, 25 February, 2096, will be the child's
birthday, if born in this century.