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The Legendary Great Aunt

2021-03-07T07:19:24.220Z


She had all the birthdays of the widely ramified family in mind, even her own life dates were mathematically well sorted. How long did the great-aunt live?


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Elisabeth was a legend: The great-aunt kept the clan together like no one else. If someone from the extensive family needed advice, she was always there.

Her number memory was impressive.

She always knew exactly which nephew and which granddaughter celebrated which birthday and when.

Her life data were also surprising - from a mathematical perspective.

The great-aunt was born in the 20th century, but unfortunately did not live to see the year 2000.

If you write your date of birth and your date of death in the form DD.M.YY, you need each of the ten digits from 0 to 9 exactly once.

But that's not all: no other person whose life data are also formed from these ten digits in the format DD.M.YY lived longer than Elisabeth.

When was Elisabeth born and when did she die?

Note: The format DD.M.YY reveals that the dates you are looking for cannot be in the months of October, November and December because the month number (M) is single-digit.

The days, however, are two-digit.

Please scroll down to find the solution!

Photo: Michael Niestedt / DER SPIEGEL

solution

Elisabeth was 95 years old and lived from April 15, 2003 to July 26, 1998.

The date format is DD.M.YY.

The year of birth should be as small as possible and the year of death as large as possible.

So 01 and 98 would be the first choice for JJ.

But there is a problem with the number 01 in the year of birth.

For the first T in the two day numbers TT, only 2 and 3 would then come into question.

However, a 3 must be followed by a 0 or a 1, because a month has a maximum of 31 days.

The 0 and 1 are already taken for the year of birth, which is why there is no solution with 01 for JJ.

02 is also out of the question for the year of birth, because then a day number would have to be 31 and none of these digits would be free for the other day number, which also has to start with 1, 2, or 3.

The smallest possible combination for the year of birth is therefore 03. The first digit of the birthday is then 1 - and the first digit of the day of death 2. Because we always try to keep the digits as small as possible for the birthday and as large as possible for the day of death.

Now the digits 4, 5, 6, 7 have to be assigned.

We start with the month so that the difference is as large as possible.

For the birth we take the smallest digit, i.e. the 4th. For the day of death, the largest digit, the 7th.

Date of birth: 4/15/03


Date of death: 7/26/98

I discovered this not-too-difficult puzzle in the book "The Bogota Puzzles" by the Colombian mathematician Bernardo Racamán.

If you missed a puzzle from the past few weeks, here are the ten most recent episodes:

  • Cleaning orgy in the restaurant kitchen

  • A triangle the size of the earth

  • Looking for a spaghetti triangle

  • Patchwork in the square

  • Three euros, three dice

  • Circles on the chess board

  • Confusion in the terrarium

  • The infinite root

  • Epidemic on the chessboard

  • Perfect Advent

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Source: spiegel

All business articles on 2021-03-07

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