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?

Consider statement 2:
If the Engineer is younger than the Doctor, then the Engineer and the Doctor are not blood relatives.
This only says in effect, if A then B. This doesnt necessarily imply if not-A then not-B. That would have to have been specified by "Only if"
If MrX is engineer and is older than his wife, they can still be unrelated; statement 2 simply becomes irrelevent. Therefore I believe that the wife is still an equal contender with her son for being the doctor.

Posted by cat on 2003-08-29 18:59:04