One of Mr. X, his wife, their son and Mr. X's mother is an Engineer and another is a Doctor.
1. If the Doctor is a male, then the Engineer is a male.
2. If the Engineer is younger than the Doctor, then the Engineer and the Doctor are not blood relatives.
3. If the Engineer is a female, then she and the Doctor are blood relatives.
Can you tell who is the Doctor and the Engineer?

(In reply to Solution by DJ)

I came to the same conclusions as you (that Mr X is engineer and either his wife or son is the doctor) but am unsure about your argument in one part starting:
'If the doctor is a female younger than the... engineer...This is possible only if Mr. X is older than his wife, and he is the engineer while she is the doctor.'
Statement 2 says 'If the engineer is younger than the doctor...', but it doesnt say 'if and only if' or 'only if.'
Therefore the possibility seems to remain that the engineer and doctor could be non-blood relatives in either case. Am I missing something?

Posted by catherine on 2003-08-27 16:15:44