Q18

[hnadgauda]

For this question, I answered it by writing out all the inferences:

1 cannot be H, S, T
2 cannot be H, T
3 cannot be T
4 cannot be R
5 cannot be R, F
6 cannot be R, S, F, G

Is there a faster way to solve this problem?

[ohthatpatrick]

You can consider starting by asking yourself, "Who CAN be 3rd?"

By the time we're doing Q18, we probably have a handful of specific scenarios we wrote out on our page (if not, you should consider writing more stuff out).

Sometimes that gets us all the way to a correct answer, other times it narrows the field so we have a specific dude to investigate.

Do you have all these rules linked together in a Relative Ordering Tree? If so, you could look at the extremes of your Tree for people that had too many people coming before/after to be 3rd.

If you can't be 3rd, you either have more than two to the left of you or more than three to the right of you.

[JohnD194]

DOn't see how D is wrong. Why cant T be in 3?

I got F R G S T H??

[ohthatpatrick]

Your scenario didn't involve T in 3rd, so how was that evidence that T can be 3rd?


F - G - T
......../
.....R - S - H


According to our rules, we know that F, G, and R all need to come earlier than T.

Since there are 3 things that must come before T, we could never put T in 3rd.
(There would only be the first two spots available for those 3 things)

Also, G can be 3rd.
F R G T S H is a legal scenario.

F can be 3rd.
R S F G T H is a legal scenario.

R can be 3rd.
F G R T S H is a legal scenario.

So we can eliminate A thru D given that we know that G, F, and R all can be 3rd.