What is the probability that on a given workday Mr. Jonathan dresses in formals, travels by car to his
office, and drinks a coffee there?
(1) Jonathan dresses in formals on alternate days, and drinks coffee AT HIS OFFICE each day he wears formals.
(2) Jonathan goes to his office by car 3 of every 5 days.
Hi frank1!
The problem is with the problem itself... this is one of the cases when we do not know if the creator of the problem is trying to trap us or if he/she was only less careful than he/she should... I will admit the first option!
(I added something in the question stem, but even so there are problems... see below!)
Answer (with considerations above and below): E
(1) BIFURCATES:
> If Jonathan NEVER goes to his office by car, then the probability asked is certainly ZERO.
> If Jonathan ALWAYS goes to his office by car, then the probability asked is certainly NOT ZERO.
Comment: the usual "is insufficient because I know nothing about the car" is not nice. What I did above is "explore" this fact to GUARANTEE (1) is not sufficient.
(2) BIFURCATES:
> If Jonathan NEVER dresses in formals and NEVER drinks coffee at the office, the answer is ZERO.
> If Jonathan ALWAYS... and ALWAYS... , the answer is NOT ZERO.
(1+2) BIFURCATES:
> If Jonathan drinks coffee AT HIS OFFICE each day he wears formals AND ONLY at these days, the answer is something.
> If Jonathan drinks coffee AT HIS OFFICE each day he wears formals BUT ALSO in additional days, the answer is different.
Obs.: why do I believe that this is what the creator of the problem had in mind? Because to solve the problem mathematically, admitting some additional info, would be better served in a Problem Solving mind, not in a Data Sufficiency one... (my opinion and GMAT teaching experience)
Best Regards,
Fábio.
