# Which one of the following could be the schedule of interviews in order from the first day through the fourth?

Nicole on September 16, 2019

Video

Hi, any chance we can have a video on the game set up and questions? I struggled on this game.

Irina on September 16, 2019

@odonnell,

Please forward your request for a video explanation to our support team. They can be reached by tapping "support" from the left menu or by calling 855.483.7862 ext. 2 Monday-Friday 9am-6pm PT.

In the meantime, please see below for a written explanation for the setup and the first question.

The game involves a prosecutors office interviewing 4 witnesses - F G H I over a four day period. Each witness will be interviewed by exactly one of three investigators- Q R S - and each investigator will interview at least one witness. The game then requires us to match witnesses to investigators and days.

I:
W: ___ ___ ___ ___
1 2 3 4

The following rules apply:

(1) G & H must be interviewed by the same investigator:

G(i)= H(i)

(2) G & I cannot be interviewed on consecutive days.

~GI
~IG

This rule tells that G & I must go on either days 1 & 3, 2 & 4, or 1 & 4.

(3) Q must interview F
Q -> F

This rule allows us to infer that Q does not interview G & H because if Q interviews F G H, there is only one person left to interview - I - but two more investigators, and the game tells us that every investigator must interview at least one witness. Hence, we can conclude that no investigator can interview more than 2 witnesses. 2 - 1 -1 is the only possible scenario of witnesses per investigator.

G& H must then be interviewed either by R or S.

(4) R must conduct the 3d interview.

I: R
W: ___ ___ ___ ___
1 2 3 4

This is an optional step, but since we know R must interview either G & H or I, we could illustrate one of the most restrictive scenarios, where R interviews I:

I: S /S/Q R S/Q
W: G /H/F I /H/F
1 2 3 4

Then S must interview G on day 1 per rule (2), and H/F could be interviewed on days 2 and 4.

Let's summarize all the inferences:

I: R
W: ___ ___ ___ ___
1 2 3 4

R/S: G & H
R/S: I
Q: F

~(GI v IG)

The question asks us which of the following could be the schedule of the interviews?

(A) Q: I, R:H

Incorrect, per rule (3), Q must interview F.

(B) Q:F, S: I, R: G, R:H

Incorrect, this schedule violates rue (2), we cannot have GI/ IG sequence

(C) R:I, Q:F, R:G, S:H

Incorrect, G & H must be interviewed by the same person per rule (1).

(D) S:G, S:H, Q:F

Incorrect, R must conduct the interview on day 3 per rule (4).

(E) S: I, Q:F, R:H, R:G

Correct. This schedule complies with all the rules.

Let me know if this makes sense and if you have any further questions.