Equivalent rule, min-max and completely determines | Quick guide

You’re being asked to identify a condition that would have the same effect on the setup, if substituted for one of the existing rules. The answer will be a condition that, when combined with the other original rules of the setup, will result in exactly the same possible outcomes as the rule it's replacing. In other words, it will restrict exactly as much as the rule it’s replacing—no more and no less.

✓ Understand the rule that you’re replacing. Notice what the rule actually says. This might seem obvious, but it can be easy to get bogged down in inferences and forget what the actual rule is. The correct choice must restrict the outcomes in the same way—so, it must meet the conditions outlined in the original rule.

✓ Understand how the rule you’re replacing relates to other rules What can you infer? For instance, if Rule 1 is that L is before M, and Rule 2 is that M is immediately before N, then we can infer that L is before N.

✓ Rule out wrong choices. It’s possible that an answer will jump out at you, but it’s unlikely. With find an equivalent rule questions, you’ll often be better off eliminating wrong choices. So, go over the choices, and see what you can infer from them. If a choice doesn’t constrain the elements in the same way that the original rule does, eliminate it. Often, wrong choices will match an inference we made from the original rule, but won’t actually give us the initial constraints of the rule. This is something to watch out for.

✓ Try it out! (Optional): If you have time, it can be a good idea to test the choice you think is right. Plug the new condition into your setup. Do you get the same inferences? If so, that’s the answer.

For these rarer questions, you’re asked to determine what the minimum or maximum number of elements are, in either the given scenario, or in a scenario with a new condition. It’s generally helpful and quicker to start with either the minimum or the maximum, so that you can eliminate choices instead of trying to find the answer immediately.

✓ If you’re starting with the minimum, look for the smallest number listed as a possible minimum in the choices Test it—does it work? Then eliminate any choices with bigger numbers than that minimum. Continue testing until you have established a minimum.

✓ From the maximum possibilities in the remaining choices, test the biggest one Does it work? Then eliminate any choices with smaller numbers than that maximum. Continue testing until you have the answer.

For a completely determines question, the answer will allow you to deduce a complete picture, once you incorporate the choice’s information. The wrong choices will lead to an incomplete picture. It’s exceedingly rare that you would be able to see the answer simply by looking at your initial diagram and rules, so it’s often best to move quickly to testing the choices.

✓ Test each choice, by incorporating the condition in the choice into a new, bare-bones diagram, and making deductions Are you able to continue making deductions all the way to a complete picture? Then that’s your answer!

✓ If you stall on deductions, remember that four of the wrong choices will lead to exactly that result! Don’t try to force a complete picture if it isn’t happening. The answer will force a complete picture without you needing to improvise.