Hi BlueDragon2010,
The other posts in this thread have properly explained the "math" behind this question, so I won't rehash that here. Instead, I'll offer some perspective on how DS questions are written. In many Quant questions, you'll be asked to solve for "one thing" (a variable, total, speed, probability, etc.); while many DS questions will ask you for a value, others will ask you a "yes/no" question. While the tactics for solving these types of questions is similar to other questions, your focus needs to be on the "consistency" of the results (and whether the results stay the same OR change). This question asks WAS the appointment on a Wednesday (a yes/no question)? MAYBE the appointment was on a Wednesday, MAYBE it wasn't. In these situations, make sure to be thorough with the possibilities and consider the options. Those considerations are the only way to be sure that you're answering the question correctly.
GMAT assassins aren't born, they're made,
Rich
