Brain Teasers
Untrue Ages
Boris Downhillski and Mad Ade have a conversation.
Boris says: "I am certainly not over 40."
Mad Ade says: "I am 38 and you are at least 5 years older than me."
Now Boris says: "You are at least 39."
All the statements by the two are false. How old are they really?
Boris says: "I am certainly not over 40."
Mad Ade says: "I am 38 and you are at least 5 years older than me."
Now Boris says: "You are at least 39."
All the statements by the two are false. How old are they really?
Answer
Boris is 41 and Mad Ade is 37.Seeing as they are both lying then the real conversation should really run like this:
Boris says: "I am certainly over 40."
Mad Ade says: "I am not 38 and you are at most 4 years older than me."
Now Boris says: "You are at most 38."
From first statement it is clear that Boris is over 40. Also, from next 2 statements it is clear that Mad Ade is less than 38. Hence the possibilities are :
Boris = 41, 42, 43, 44, 45, ......
Mad Ade = 37, 36, 35, 34, 33, ......
It also says that the difference between their age is maximum 4 years. Hence, there is only one possible pair i.e. 41 and 37, all other combination have differences more than 4.
Hence the answer - Boris is 41 and Mad Ade is 37.
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Comments
hmmm. if you say something isn't black that does not mean it is white. if x is not at least 5 years older than y, that could also mean he is at least 6 years older.
By saying that x is at least 5 years older than y, then x is a member of the subset (y+5)
I found this one confusing. I couldn't tell who you were refering to when you said you and I
doesn't make sense at all.......just because she is not x amount of years younger than him, that does not not mean she has to be a certain age. Not a good brain teaser.
changed my mind it makes sense now....sorry.
The second statement's explanation isn't correct. For it to be false, either the first part or the second part (or both) need to be false. The other can be true without affecting the falsehood of the statement.
Right. The literal negation of Mad Ade's statement is:
"I am not 38 OR you are at most 4 years older than me." (or both, which is implied by the logical or)
You need to interpret Mad Ade's comment as two separate statements
for the solution to be unique.
"I am not 38 OR you are at most 4 years older than me." (or both, which is implied by the logical or)
You need to interpret Mad Ade's comment as two separate statements
for the solution to be unique.
dewtell and smertios say it all. ambiguous negation of second statement leads to multiple answers
dewtell and smertios say it all. ambiguous negation of second statement leads to multiple answers... the only good part is now we know how old mad-ade is!
i thought this one was good. one of the few i actually got right!
i DON'T GET IT.
I got it right. However, one question. Couldn't Boris be 42? The converse to the statement "...at least 5 years" could be taken as "...at most 5 years", which may provide an alternative solution. For the purpose of the puzzle, I suppose one could find the smallest possible age difference, which would give the right answer, but it seems to depend on how you interpret that one statement.
Good puzzle
Good puzzle
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