What these tests in general lacks is removing any obvious problems, and let the contestant find the problem self. That usually only rely on high rationallity.
Normal intelligent people can only solve problems they know are there, why only 2 so far has solved this anectdote, that be myself and a brilliant dude I know, it has been presented to about over 500 people.
Story of the 2 Garbage Men
I have a brilliant doctor friend, who uncritically told me a story he heard in a auditorium filled with fellow doctors at Panum (danish educational institute ..or something)
This story he told me I will propose as a challenge to this forum.
2 garbage men, who had been in the buisness for 2 decades, who had sufferd foul odeurs through out their career, took on a vacation to Turkey and went to the perfume streets.
As they walked the one would become ill, and in the end fell to the ground. The helpful perfume sellers would aid the poor man with their smelling salts, but only making him go to a deeper coma.
The other garbage man would realize it was the thick odour in the street that caused the problem, and pulled his friend out to cleaner air, which helped and he would awaken from the coma.
Conclusion: each their scent.