I have the same question
Why can't it be Q G L/N P N/L P?
Reggieon February 17, 2021
The question is asking us which days can Pizza be offered twice, since we already know it's offered on Thursday.
Rule #5 is that Pizza's can't be on Saturday, and must be on Thursday.
Rule #2 says that Pizza can't be consecutive, so combining it with the above, Pizza cannot be on Wednesday, Friday, or Saturday. That leaves us with only Monday or Tuesday.
Rule #4 says that Quesadilla must come immediately before Gazpacho.
Rule # 6 says that Quesadilla cannot be on Friday, which combined with #4 means that Gazpacho cannot be on Saturday, because Quesadilla couldn't be on Friday.
Gazpacho also can't be on Monday for the same reason, leaving it only for Tuesday or Wednesday.
Combining this with the Pizza, if Pizza were on Tuesday, there would be nowhere for the Quesadilla Gazpacho block, which is why you can eliminate Tuesday.
If Pizza is on Monday (and Gazpacho were on Wednesday, we have a valid formation:
M-P, T-Q, W-G, R-P, F-N/L, S-L/N
