Q21

[shehadehr]

I cannot find where to post the "subject" for new topic!

Quick question, how is the answer B and not D? If, J is in 3 then J is also in 8, but this violates constraint 4...

Am I missing something?

my setup is like this:

_ _ _ _ _ _ _ _ _ _
1 6 2 7 3 8 4 9 5 10

I put O is 4 and O in 9, so then J's have to go in 5 and 10, and since M comes before O and J, and since k and L have to be split up, I use all this, hit the questions, eliminate A B C and E, so D is left by default. Seriously not seeing B as the right answer at all

Edit: Nevermind, my answer key was wrong. However, could someone take a look at my setup and let me know what they think? I feel like it worked well and I was fast. I think what helps is that you remember if the same letter has to always go in the given paired laps (ie, laps 1 & 6: if its stated that M is in 1, then you know M is in 6 too, also, keeping in mind the M--OJ contraint, as well as others).

[ManhattanPrepLSAT1]

Hey Ray!

You've got it. If you put O in 4+9, then J will go in 5+10.

_ _ _ O J _ _ _ O J

At this point M, K, and L are a bit up in the air. But that's okay, lets hit the answers. We need to find one that could be true.

(A) must be false as J swims laps 5 and 10.
(B) must be false as J swims laps 5 and 10.
(C) must be false as J swims laps 5.
(D) could be true.
(E) must be false as J swims laps 5.

Btw, your setup looks good! Here's a hint though, did you try framing this one? You might find that since the OJ chunk is limited to only 3 places, you might be able to work through the questions more quickly.

[Crogati]

I am confused how (c) is the answer. Doesn't L in spot 3 force K in spot 2 thus violating the rule "no KL"?

[sumukh09]

I am confused how (c) is the answer. Doesn't L in spot 3 force K in spot 2 thus violating the rule "no KL"?

D is the answer for 21

[ManhattanPrepLSAT1]

D is the answer for 21

Thanks sumukh09! Also, for Q21 if L swims in lap 3, that does not force K into lap 2. One possibility is that it goes

K M L O J K M L O J

This can be seen in the middle frame in the middle of the 3 following frames based on placing the OJ chunk: