In my understanding the OR rule indicates that one of them MUST happen. It cannot be that both cannot happen. It's either M-J or J-N. One of these two must happen.
A or B but not both means one must be in at the exclusion of the other.
I broke this down as either M-J or J-N but not M-J-N, so the four possible orders are: N-M-J, M-N-J, J-N-M, or J-M-N.
It can't be N-J-M because the rule states that J must be either after M, or before N, and neither is the case in the N-J-M ordering. It has to meet one of those specifications, but can't meet both of them, and it also can't meet none of them, due to the way the stimulus is worded. Hope that helps, let me know if you have any questions.
@mheannarino said: Rule: "J will arrive after M or before N, but not both"
Correct translation: N and M arrive before J or they both arrive after J.
I would diagram this as:
Some LSAT Trainer rule notation for ya (though I could almost swearsies I've seen this on 7sage as well?). When I have a "this one OR that one but not both" rule I notate that with both options separated by an underlined "OR."
Comments
A or B but not both means one must be in at the exclusion of the other.
It can't be N-J-M because the rule states that J must be either after M, or before N, and neither is the case in the N-J-M ordering. It has to meet one of those specifications, but can't meet both of them, and it also can't meet none of them, due to the way the stimulus is worded. Hope that helps, let me know if you have any questions.
J--N <-------> /(M--J)
M--J <-------> /(J--N)
Some LSAT Trainer rule notation for ya (though I could almost swearsies I've seen this on 7sage as well?). When I have a "this one OR that one but not both" rule I notate that with both options separated by an underlined "OR."