statement 1)

exactly 84 hrs before was Monday...

hence if the appointment was at 12:00 in the afternoon on Friday,
then 84 hrs before would be exactly on Tuesday at 00:00 am

now if we alter the appointment timing then 84rs before it would be either be Tuesday or Monday and vice versa... i.e if u start on monday, then the appointment could be on Friday or Thursday...
Hence insufficient
Statement 2)
by itself insufficient

together:
The Appointment will always fall on Friday..
Hence sufficient...

IMO: C

pradeepkaushal9518 wrote:If Julio had a dentist's appointment on a certain day, was the appointment on a Friday?

Exactly 84 hours before the appointment, it was Monday.
The appointment was between 2:00 p.m. and 8:00 p.m.
A Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D EACH statement ALONE is sufficient.
E Statements (1) and (2) TOGETHER are NOT sufficient.

C?

By itself, (2) is clearly insufficient. Eliminate B and D.

From (1) we learn that the appointment was exactly 3.5 days (3 days and 12 hours) after sometime on Monday. If it is the latest possible time on Monday--Monday-midnight (or right before midnight), then 3 days would take us to Thursday midnight and the extra 12 hours would run us to Friday at noon. However, if it's Sunday-midnight (or just after midnight), we would only get to Thursday noon. Thus, from (1), we can only determine that the appointment was sometime between Thursday noon and Friday noon. Eliminate A.

(1) + (2):

From (1), we know that if the appointment was on Friday, the latest it can be is at noon. From (2), we know that the appointment was between 2pm and 8pm. Thus, the appointment cannot have been on Friday. So, we can provide a definite answer to the question: was the appointment on Friday?...definitely NOT.

Thus, the answer is C.