June 2002 LSAT Section 3 Question 19

# Which one of the following could be an accurate list of the swimmers of the first five laps, in order from lap 1 thro...

3 Replies

Ben on December 10 at 05:12PM

Hi DDL, thanks for the question.I will look into the video explanation for you, but for now I will hopefully provide some help through here!

This game presents us with 5 variables: J, K, L, M, O

Each variable is placed twice and we know the following: 1 and 6 are the same, 2 and 7 are the same, 3 and 8 are the same, 4 and 9 are the same, and finally, 5 and 10 are the same.

So in essence, we just need some way to remind ourselves that 1-5 and 6-10 are the exact same order. Perhaps putting a line through the middle of 5 and 6 could work, as follows:

__ __ __ __ __ I __ __ __ __ __

1 2 3 4 5 6 7 8 9 10

Additionally, we can draw the two sets (1-5 and 6-10) stacked.

__ __ __ __ __

1 2 3 4 5

__ __ __ __ __

6 7 8 9 10

Or, if you feel more comfortable noting everything out explicitly, you may write in your rules:

1 = 6

2 = 7

3 = 8

4 = 9

5 = 10

Now for the rules:

KL in a crossed out block. This also means that we cannot have if K is in 5, then L cannot be in 1, because L would also be in 6 and this violates the rule.

J does not go in 9 (by extension, not in 4 as well)

M - O, simple sequencing rule. This means that M cannot go 5th nor 10th, and O cannot go 1st nor 6th.

At least one block of OJ. It might appear that we would always place OJ in a block if one pair is already in such a placement. Consider if we put O and J in 2 and 3 respectively. Then it would __ O J __ __ I __ O J __ __

1 2 3 4 5 6 7 8 9 10

However, the at least one in this rule allows for the following possibility.

J __ __ __ O I J __ __ __ O

1 2 3 4 5 6 7 8 9 10

Please let me know if this was helpful as far as setup goes. And let me know if you have any other questions!

Dustin on December 10 at 10:03PM

Thank you!Ravi on January 14 at 10:22PM

@DDL, let us know if you have any other questions!