Last Updated on May 9, 2023
GMAT OFFICIAL GUIDE DS
Solution:
We need to determine whether Juan’s appointment was on Wednesday.
Statement One Alone:
Exactly 60 hours before the appointment, it was Monday.
Although we are given that 60 hours before the appointment, it was Monday, we don’t have enough information to determine whether his appointment was on Wednesday. Let’s test a few cases to show this. Let’s first convert 60 hours into days.
Case #1. Assume that it is early Monday, at 1 am. Go forward 60 hours (which is 2 days and 12 hours) and the appointment is Wednesday at 1 pm.
Case #2. Assume that it is late Monday, at 11 pm. Go forward 60 hours (which is 2 days and 12 hours) and the appointment is Thursday at 11 am.
Thus, we see that the appointment could have been on either Wednesday or Thursday. Statement one is not enough information to answer the question. We can eliminate answer choices A and D.
Statement Two Alone:
The appointment was between 1:00 pm and 9:00 pm.
Since we are not given a specific day, statement two is not sufficient to answer the question. We can eliminate answer choices A and D.
Statements One and Two Together:
From statements one and two we know that exactly 60 hours before the appointment it was Monday and that the appointment was between 1:00 pm and 9:00 pm. Let’s test two cases in which the appointment is at 1 pm on Wednesday and at 9 pm on Wednesday and see whether 60 hours (2 days and 12 hours) prior falls on a Monday.
Case #1 – appointment at 1 pm Wednesday
1 pm Wednesday – 60 hours = 1 am Monday.
If this is hard to see, we can break this into two increments:
1 pm Wednesday – 2 days = 1 pm Monday, and
1 pm Monday – 12 hours = 1 am Monday.
Case #2 – appointment at 9 pm Wednesday
9 pm Wednesday – 60 hours = 9 am Monday.
If this is hard to see, we can break this into two increments:
9 pm Wednesday – 2 days = 9 pm Monday, and
9 pm Monday – 12 hours = 9 am Monday.
Had the appointment fallen between 1 pm and 9 pm on Thursday, 60 hours before the appointment would have been between 1 am and 9 am on Tuesday, respectively. Similarly, had the appointment fallen between 1 pm and 9 pm on Tuesday, 60 hours before the appointment would have been between 1 am and 9a m on Sunday, respectively. Since either scenario does not fulfill the information given in the statements, we see that the appointment must have fallen on Wednesday.
Answer: C
