# It's his birthday!

A friend of mine told me that he was about to have his birthday. However, he didn't tell me what his birthday was.
When is his birthday?

Compulsory Hint 0

He is sixteen years old

Compulsory Hint 1

His favourite color:

• Just mathematics tag? I feel like there should be an enigmatic puzzle tag too. Also, I think you should change 'However, he didn't tell me what his birthday was.' to 'However, he didn't tell me when his birthday was.'
– Duck
Sep 30, 2019 at 0:30
• No problem! (adding this for the character limit).
– Duck
Sep 30, 2019 at 0:38
• This seems underspecified. Puzzles in general should incorporate clues to how they should be solved - as part of the puzzle itself, not grafted on over time in spoiler-tagged "hints". If a hint is effectively required for anyone not inside your head to solve the puzzle then it's not a "hint", it's an essential part of the puzzle--and in many cases is the only thing preventing your puzzle from being "guess what I'm thinking". Note too that the enigmatic-puzzle tag means the solver "must deduce what type of puzzle it is"--but that deduction needs to be possible from what's provided. Is it?
– Rubio
Sep 30, 2019 at 3:03

The birthday is on

March 13
The two clues suggest using the hexidecimal representation (16th birthday) of the displayed color which is #910313 or 1991-03-13

• I've considered this version too, but then he will be about 28 years old (as of 2019). Of course, the dialogue could take place in 2007. +1 nevertheless. Oct 1, 2019 at 9:04
• @trolley813 My take on it was that he wasn't really 16 yrs old. That was just a clue to use hex for the color scheme. However, now that I think of it, it doesn't make much sense since it would conflict with the year included in the hex date. Oct 1, 2019 at 9:14
• Sorry, I didn't consider that. However, you are correct! Oct 1, 2019 at 13:49
• @KSharing Wait, the hint was necessary for the answer?
– Duck
Oct 2, 2019 at 3:07
• Yes (adding this for the character limit) Oct 2, 2019 at 3:23

The title says "It's his birthday!"

Maybe today is his birthday!
You posted the question right after midnight. So your friend told you yesterday that he is about to have his birthday, and now it is his 16th birthday as your hint says he is (now) 16 years old.

• This is not the correct answer. Add oil! Oct 1, 2019 at 7:31
• I haven't uploaded all clues yet Oct 1, 2019 at 7:31
• @KSharing The riddle should be solvable without any hints as Rubio already pointed out. Is this riddle solvable WITHOUT your hints? Oct 1, 2019 at 7:50

His birthday is:

possibly, on October 31st

Because

the displayed color is #910313 in hexadecimal. Since he is 16 years old (as of 2019), so "3" or "03" must be the year (2003). He was about to have his birthday (as of 2019-09-30), so it's most likely in October. So, we find an explanation (actually, one of them): 9-10-31-3, meaning 9:00, 10/31/2003 (i.e. he was born at 9 AM on October 31st, 2003).

• If he is 16 years old, but yet to have his birthday this year, that would mean born in '02 Oct 1, 2019 at 8:51

His birthday is:

14th March

Because:

His favourite colour has the RGB value: 145/3/19 Which looks like a date of this year.
I assume the 5 was added to 14 because otherwise all the numbers would be very small and the colour is then practically black.