22
votes
Accepted
Find the lower 8-digits number such that
Solution (0 allowed)
Reasoning
Solution (0 disallowed)
Reasoning
- 130k
11
votes
Accepted
Numbers whose product of digits is a multiple of sum of digits
Three numbers
Observe that:
Moreover:
So we can start by finding...
At this point it is worth noting that:
So we search and find that
Now observe that:
So:
With this much flexibility for ...
- 749
6
votes
Important Alien Message
Not an answer.
Alphabetic transcription of alien writing:
QBADFAHGCAEBACDABEA
FIJCHAEGADFAIEAAHA
DGBACAFEILIAGADBAAA
AAAFCEADHAGBNEAIFAB
HDGAIEFAGCHAFADMEF
AHCABIADACHEGADBAO
AHDACFIEAHDBAGEIAH
...
- 1,208
6
votes
Accepted
Equilibrium of differences
(NB: I've chosen to interpret "the four numbers Alice chooses must be non-repeatable" as "Alice cannot choose the same digit more than once". There are other possible ...
- 71.5k
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