- Thu May 15, 2014 10:02 pm
Thanks for posting.
K and O can not be together, they have to be next to each other, in either order. (KO/OK). So for question #1, that immediately rules out answer choice C. H and Z are also not together, because according to the first rule: H > Z. That rules out B. Since K and O need to be right next to each other (rule 3), and I has to be on Thursday (rule 2), we also can think about the overall sequence.
That is: __ __ __ _I_ __
M T W R F
Notice that with I on Thursday, the only way that K or O could be on Friday would be if Thursday has two people. But in the local role for #1, 2 people are on Tuesday. With 6 people fit into 5 days (and one per day except for one day with two students), only one day will have two people. That means only I can be on Thursday, so K and O must come before I in order to be placed together. K & O could go Monday or Tuesday, or Tuesday and Wednesday, to comply with the rule. Notice that either way, one of them will go on Tuesday (with the other on either Monday or Wednesday). Therefore we can rule out any answer choice that doesn't include either K or O on Tuesday. That is, the right answer choice can't have both K & O, but must have one of them. That makes it pretty clear, the only remaining answer is D.
For question #4:
We need to find a day which, if it includes Z, will fully determine the schedule. The only rule we have about Z is that Z comes some time after H. That is Z is not on Monday. So that rules out answer choice A.
You can check each remaining answer choice to see which one places U for sure. My instinct however is to start by checking what happens if Z is on Thursday, because putting Z with I on Thursday again will give us information about where K & O have to be.
__ __ __ Z+I __
M T W R F
Again, because K & O need to be next to one another (rule 2), we know neither can go on Friday, since Thursday is already full. We also know H precedes Z, based on rule 1, so it can't go on Friday. To make sure that one person is seen every day then, the only person left who can go on Friday is U. Therefore if Z is on Thursday, that determines that U is on Friday. So the correct answer choice is D.
Hope that helps!