The following list contains the room numbers of some of my co-workers:

  • Room 15: Bobbie Solomon, born 18-Apr-1973
  • Room 21: Galvin MacNeil, born 24-May-1974
  • Room 22: Ismael Tirrell, born 7-Feb-1964
  • Room 31: Lorene Alberts, born 22-Jun-1992
  • Room 42: Robert Cabello, born 27-Sep-1967
  • Room 48: Olivia Perkins, born 25-Jan-1971
  • Room 52: Nelson Morales, born 19-Oct-1987
  • Room 65: Alfred Bennett, born 11-Jul-1988
  • Room 73: Buster Robbins, born 6-Aug-1989
  • Room 84: Dorris Compton, born 13-Nov-1985
  • Room 87: Tamara Pierson, born 15-Dec-1970
  • Room 97: Ursula Akiyama, born 30-Mar-1990

What will be the room number of my co-worker Martin Petters, born 16-Oct-1984?

  • 1
    $\begingroup$ Whatever company you work at has serious issues with their office assignments. $\endgroup$ Feb 9, 2015 at 20:27
  • $\begingroup$ There are no 14 red herrings... $\endgroup$
    – EKons
    Jul 1, 2016 at 16:06

2 Answers 2


Martin Petters is in room 16.


By flipping the initials of the co-workers and by flipping the digits of their room numbers, you get the corresponding element numbers of the corresponding chemical elements.
The birth dates are red herrings.

Step by step solution:

15 Bobbie Solomon - 51 Sb Antimony
21 Galvin MacNeil - 12 Mg Magnesium
22 Ismael Tirrell - 22 Ti Titanium
31 Lorene Alberts - 13 Al Aluminium
42 Robert Cabello - 24 Cr Chromium
48 Olivia Perkins - 84 Po Polonium
52 Nelson Morales - 25 Mn Manganese
65 Alfred Bennett - 56 Ba Barium
73 Buster Robbins - 37 Rb Rubidium
84 Dorris Compton - 48 Cd Cadmium
87 Tamara Pierson - 78 Pt Platinum
97 Ursula Akiyama - 79 Au Gold
16 Martin Petters - 61 Pm Promethium


I do not know the answer yet, but I have done some observations. I post them here so others could maybe benefit from them.

There are 12 persons in 12 rooms, with number 13 to be placed.

All names have equal number of letters, 6 in firstname, 7 in lastname, in total 13 letters. Firstnames seems to start with different letters, but Bobbie and Buster disrupt the pattern. Same goes with lastname, but here there are three pairs on A, C and P.

All dates are different.

All days of the month is different as well.

All Months are different, except the one to be placed.

All years are different as well. Some are ending in the same digit, and this shows some relation to the last digit of the room number. But here there are a break in the pattern as well.

These are the undisputable facts.

Here comes some of my speculations also:

I suspect that the number 12 is central to this puzzle. There are 12 Months, and since they are never used twice, I do think that two persons born in the same Month would be revealing to the puzzle.

Since a lot is different, but still similar, I suspect that all parts of name and birth date is needed. It looks like a calculation of some sort. (This could however just be a trick of concealing the clue in between unnecessary hints). 13 letters combined with the month number could also lead to something.

Another point to consider is whether the room numbers has to be unique (that means running numbers, building on eachother), or that if the right person with the right birth date comes along, someone would needed to share a Double room?

  • $\begingroup$ You need to "spoiler them", using >!spoiler syntax. $\endgroup$
    – EKons
    Jul 1, 2016 at 16:07

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