If Alicia takes Statistics at 3 P.M. and Geography, then which one of the following courses must she also take?
tomgbeanOctober 22, 2019
Stumped
I was able to narrow my answers down to J R and M but since the rules says J/R and J/M I couldn't tell which one had to be in. It would seems that either of them could be in. For example you could have J and R in together or you could have R and M in together. J appeared twice in the options so I chose J as my answer. Could you explain why R is the correct answer? Thanks!
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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.
tomgbeanOctober 22, 2019
Got it!Thanks!
EmmaklivelyJune 21, 2021
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?
Emil-KunkinJanuary 6, 2024
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.
