Q5

[AyakiK696]

I kind of felt tricked by this question; I was attracted to answer choice C, because it basically follows the same rule as the one it's being substituted for, but it almost felt too easy. If such an obvious answer choice had not come up, would the best method to approach this question have been simply testing out each answer choice? I tend to find these types of questions very time consuming.

[ohthatpatrick]

A correct answer has to give us the exact same game, which we can measure in two ways:

1. Does this new rule prevent anything that used to be allowed? (Is it too RESTRICTIVE?)
use previous work to find counterexamples to these new rules. If you have a counterexample, you know this new rule is not correct.

2. Does this new rule ALLOW something that used to be forbidden? (Is it too PERMISSIVE?)
test whether this new rule forces the same limitation that the rule we're replacing gave us

Basically, think about what "work" the old rule did:
in this case, it forced M - L

For each new rule we're offered, we'll ask ourselves, "Does this force L to be later than M?"

[StephanieS945]

Hi,

The way I was quickly able to select (C) was referring to the original rules I set up. I originally combined rules 3 & 4 together to create [JM]-L, with J & M being interchangeable since the 3rd rule states M is immediately before or immediately after J. Thus, L is guaranteed to come after M AND J (regardless if M comes before J or after J).

Answer C says this rule in the reverse as "J must come before L", thus it serves the same function as M-L rule. Let me know if anyone sees any risks with solving it this way or if I need to test answers out before I can be confident C is correct.