LSAT Study question?

Question

For some reason this is not making sense to me. I know that this is extremely basic, but I think I need to see someone's perpective.

The children go to the park only if the sun is shining.

Please give me the contrapositive. Please explain which one is your sufficient condition and your necessary condition and why.

Answer 1

The diagram is: Children go to park ----> sun shining

The contrapositive is: NOT sun shining ----> NOT children go to park

The first diagram is has "sun shining" as the necessary condition because "sun shining" is modified by the necessary condition indicator "only if." That leaves "children go to park" as the sufficient condition. The contrapositive simply reverses the two terms and then negates each.

Note that if you changed "only if" for "when" in the sentence (as is done in L1HW drill #8, then the original diagram would be: sun shining ----> children go to park. That diagram drives people nuts because they try to apply a real world view to the relationship, but there is no "real world" in action. Diagrams for any conditional statement don't reflect the real world or what you think should happen, they reflect what the author said.

I hope that helps.