If Kevin's session meets on the day before Nessa's, then which one of the following is a complete and accurate list o...

Skylar on August 4, 2020

@Sam11111, thanks for letting us know! Our team is currently in the process of creating more video content, but in the meantime I am happy to provide you with a written walkthrough.

Let's start with the game setup:

JKLNOR

AM __ __ __
PM __ __ __
W T F

Rule #1: We must have K and R on the same day
Rule #2: We cannot have L and O on the same day
Rule #3: N = PM
Rule #4: J = at least one day> O. [I did not write this as J>O because I wanted to be sure to remind myself that we are talking about days, not just time slots.]

Before proceeding to the questions, we should look for deductions we can make. Rule #1 tells us that K and R must go on the same day, which is a significant restriction. We should start there. Let's set up a few hypotheticals:

HYPO 1:
Let's see what happens if we place K and R on Wednesday. Remember, we don't know which variable is assigned to which slot on Wednesday. This gives us:
AM (K/R) __ __
PM (R/K) __ __
W T F
Rule #4 tells us that J is on an earlier day than O, so we know that J will go somewhere on Thursday, while O will go somewhere on Friday. This gives us:
AM (K/R) (J/?) (O/?)
PM (R/K) (?/J) (?/O)
W T F
Rule #2 tells us that L and O cannot go on the same day, so L must be assigned to Thursday. This leaves N to fill the last spot on Friday. Rule #3 tells us that N must go in the afternoon spot, which means that O must go in the morning spot. This gives us:
AM (K/R) (J/L) O
PM (R/K) (L/J) N
W T F

HYPO 2:
We can place K and R on Thursday and go through the same logical steps above to get:
AM (J/L) (K/R) O
PM (L/J) (R/K) N
W T F

HYPO 3:
We can place K and R on Friday and go through the same logical steps above to get:
AM (J/L) O (K/R)
PM (L/J) N (R/K)
W T F

These three hypotheticals set up all of our game possibilities and will save us notable time and effort when answering the questions. We were tipped off to setting up the hypotheticals by the significant restrictions imposed by the rules.

Now onto our question. We are told that Kevin's session meets on the day before Nessa's. In which of our three hypotheticals is this the case? The second! Therefore, if we were able to deduce the hypotheticals above, we could solve this quickly by referencing HYPO 2. Here we have R and K as options for the Thursday afternoon session, so our answer is (B).

Does that make sense? Hope it helps! Please let us know if you have any other questions.