1) Not sure of which day the meeting took place. Only time is given.
Insufficient.

2) If the meeting had taken place exactly 66 hours before actual commencement time, it would have been Tuesday.

But we don't what the actual commencement time is. It could be any time of the day and we cannot say for sure whether it will be on Friday or Thursday.

Combined, Yes, we know for sure that meeting will commence only on a Tuesday. Sufficient.

The answer is C because when you combine both A and B, answer states that meeting cannot happen on Friday between 9 AM and 5 PM.

Here is my reasoning:

From (A) : The meeting took place at a certain hour between 9:00 a.m. and 5:00 p.m.

Not sufficient.

From (B) : If the meeting had taken place exactly 66 hours before its actual commencement time, it would have been on a Tuesday

OK. Needs some calculation here. Let us execute with 2 options.

If you can picturize the problem, it becomes easy. Let me try typing in .

The below numbers are in hours ( for any day):

0 ( beginning of day) 12 ( afternoon) 24 ( End of day)



Tue ( 0 12 24) Wed ( 0 12 24) Thru ( 0 12 24) Fri ( 0 12 24)



Option 01: Beginning of the day

Let us assume meeting starts early morning Friday at 0 Hours. Now go backward:

0 hours(Fri) - 0 hours ( Thur) = 24 hours
0 hours(Thur) - 0 hours(Wed)=24 hours
0 hours ( Wed) - 12 hours ) Tue) = 12 hours

Here already 60 hours is done and if you add 6 hours, it answers that meeting could have happened on Friday

Option 02 : End of day

24 hours(Fri) - 24 hours ( Thur) = 24 hours
24 hours(Thur) - 24 hours(Wed)=24 hours
24 hours ( Wed) - 0 hours ( Wed) = you need another 24 hours!

Therefore, you need 72 hours to reach Tuesday end of day. Hence, the meeting would not have happened on Friday. I hope you understood this .

Option A and Option B

The problem states meeting happened between 9 AM and 5 PM.

(1) Assume meeting happened at 9 AM Friday.

9 A M(Fri) - 9 AM ( Thur) = 24 hours
9 A M(Thur) - 9 AM(Wed)=24 hours
9 A M ( Wed) - 24 hours (Tue. End of day) = 9 hours

Therfore, 24+24+9 = 57 hours. Hence, meeting didn't take place at 9 AM

(2) Assume meeting happened at 5 PM Friday.

5 P M(Fri) - 5 P M ( Thur) = 24 hours
5 P M(Thur) - 5 P M(Wed)=24 hours
5 P M ( Wed) - 24 hours (Tue. End of day) = 17 hours

Therfore, 24+24+17 = 65 hours. Hence, meeting didn't take place at 5 PM Friday.

Hence, from C, we can exactly arrive at the answer. If in case, the meeting was scheduled at 6 PM, the answer will be correct.

Hope, I was able to explain it properly.

Regards,
Viju

thanks pap & viju for the explanation....