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SuperPrep B Logic Game #2 Question 10
Posted: Mon Jun 03, 2013 7:34 pm
by mistd
I don't understand the relationship between firs and maple.
Re: SuperPrep B Logic Game #2 Question 10
Posted: Mon Jun 03, 2013 7:47 pm
by CardozoLaw09
1.Maples --> ~Yews
2. Firs --> ~Pines
3.~Yews --> L or O (not both)
4.~(L+O) --> F +S
Combine 1. and 3. to yield: Maples -->~Yews--->L or O (not both)
10. If Firs are not in the park then from the contrapositive of 4. we know that both L and O must be in the park. If both L and O must be in the park then maples can't be in the park because that would require, from the combined conditional statements of 1. and 3. to have either L or O in the park. So by deduction Maples cannot be in the park.
Re: SuperPrep B Logic Game #2 Question 10
Posted: Mon Jun 03, 2013 8:00 pm
by mistd
CardozoLaw09 wrote:1.Maples --> ~Yews
2. Firs --> ~Pines
3.~Yews --> L or O (not both)
4.~(L+O) --> F +S
Combine 1. and 3. to yield: Maples -->~Yews--->L or O (not both)
10. If Firs are not in the park then from the contrapositive of 4. we know that both L and O must be in the park. If both L and O must be in the park then maples can't be in the park because that would require, from the combined conditional statements of 1. and 3. to have either L or O in the park. So by deduction Maples cannot be in the park.
But how do we know that both L & O are in the park from the contrapositive of 4?
I thought the contrapositive of 4 was:
~F or ~S --> L or O
Thank you!