Stumped

@tomgbean If A takes S at 3 pm and G, which of the following courses must she take? She needs to choose four courses out of 7 - G J M P R S (9 am and 3 pm) and WH. We know that she takes S at 3 pm and G. S G __ __ We can infer that she cannot take P because this would require her to take statistics at 9 am. We can infer that she cannot take WH because she must take either G or WH but not both. Thus the only remaining classes she could choose from are J M R. The rules tell us that she cannot take J if she takes M, meaning she can only take either J or M: M -> ~ J J -> ~ M Since we have three courses to choose from and we can only pick 1 out of M/J, we know that she must definitely take R and either M or J, so the full course listing could be either: (1) S G R J (2) S G R M Let me know if this makes sense and if you have any further questions.

Got it!Thanks!

I also narrowed it down to J R M but then got confused. Couldn't we have also said that she had to take (J or R) (either or ) and therefore must take M?

Nope, because there is a valid possibility where she doesn't take m. Therefore she doesn't have to take m. There is not a valid possibility where she doesn't take R, so she must take r.