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October 2015 LSAT
Which one of the following must be true?
on March 14, 2020
Please explain answer
Please explain answer.
on March 14, 2020
The answer to "must be true" questions is most often found in the initial setup. The game requires us to determine the schedule of 5 students - G H J K L who work exactly two shifts for a total of ten shifts over five days.
1 ___ ___ ___ ___ ___ G __ G H or J
2 ___ ___ ___ ___ ___ LL J H
M T W Th F
The rules tell us that:
(1) No student works both shifts of any day, so we must have two different students each day.
(2) L works the second shift on two consecutive days.
This rule tells us we must have LL combination somewhere in our schedule for the second shift.
(3) On two nonconsecutive days, G works the first shift.
(4) K works on T & F.
(6) H & J work on the same day as each other at least once.
(6) G & L never work on the same day as each other.
This is a restrictive rule, let's think about possible combinations,
G K ___ H G
__ L L J K
__ K G H G
L L __ J K
H G __ __ G
J K L L K
Note that H & J shifts are interchangeable for each of these scenarios.
Now let's look at the answer choices:
(A) G does not work on T.
Incorrect, scenario 3 allows G to work on T.
(B) H does not work on W.
Incorrect because there are no restrictions on when H's second shift must be. One of his shifts must be with J but his second shift is a free variable and could be on any open day.
(C) J does not work on T.
Correct. In all three scenarios, K & L or G & K must work on T.
(D) J does not work on Th.
Incorrect. Scenario (1) allows J to work on Th.
(E) L does not work on T.
Incorrect. Scenario 2 allows L to work on T.
Let me know if you have any other questions.
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