Linear Logic Game that can't be solved Forum

[parismade12]

HI

Any help on this would be much appreciated. I am a solo studier a month away from LSAT

The question is:

If Chris rows fourth, then Garry rows in seventh
position and Ben rows in fifth.
If Anna does not row second, then Ben rows in
sixth position and Dana rows in second.
Frank rows in the position immediately after Ben.

If Evan rows first and Dana rows third, then
how many possible configurations of the
Argonauts are there?

**

The answer is FIVE.

**

But don't the contrapositives state that B can't be 6th, and if G is 7th then C is 4th.

Thus the only options would be EAD followed by: BFGC, CBFG, CBFG; and *not* BFCG (as C would need to be 4th), and *not* GCBF (as B can't be 6th).

Any guidance much appreciated, as I say.

Thank you.

best
Harry

[It's from McGraw-Hill's LSAT logic games 2nd ed, linear game #2.]

[JohnnieSockran]

HI

Any help on this would be much appreciated. I am a solo studier a month away from LSAT

The question is:

If Chris rows fourth, then Garry rows in seventh
position and Ben rows in fifth.
If Anna does not row second, then Ben rows in
sixth position and Dana rows in second.
Frank rows in the position immediately after Ben.

If Evan rows first and Dana rows third, then
how many possible configurations of the
Argonauts are there?

**

The answer is FIVE.

**

But don't the contrapositives state that B can't be 6th, and if G is 7th then C is 4th.

Thus the only options would be EAD followed by: BFGC, CBFG, CBFG; and *not* BFCG (as C would need to be 4th), and *not* GCBF (as B can't be 6th).

Any guidance much appreciated, as I say.

Thank you.

best
Harry

[It's from McGraw-Hill's LSAT logic games 2nd ed, linear game #2.]

The contrapositives don't state that B can't be 6th. Only that if B is not 6 OR if D is not 2, then A is in 2. So A is in 2, but B can still be 6 unless I'm missing something.

The contrapositives also don't say that if G is 7 then C is 4. They state that if G is NOT 7 then C is NOT 4.

Might need to refresh on contrapositives:
1. Flip the if/then terms
2. Negate both
3. change AND to OR and OR to AND

[parismade12]

Johnnie,

This is really helpful, thank you. I hadn't come across the AND/OR switch in the McGraw-Hill textbook, the system makes more sense now.

Thanks for replying.

Is there a textbook you'd recommend for guidance? I'm about to switch to the official LSAT SuperPrep book, and have tests #52-81.

[JBird]

Johnnie,

This is really helpful, thank you. I hadn't come across the AND/OR switch in the McGraw-Hill textbook, the system makes more sense now.

Thanks for replying.

Is there a textbook you'd recommend for guidance? I'm about to switch to the official LSAT SuperPrep book, and have tests #52-81.

Get the Logic Games Bible and thank me later.