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I am not sure which is the sufficient and which is the necessary condition.

The statement:

Jenny will have lots of balloons at her birthday party. There are no balloons yet, so today is not her birthday.


How do I diagram this one? Is it:

BL->BD, contra: ~BD->~BL

OR

BD->BL, contra: ~BL->~BD

I think it is the second one because that would equate to, "If it is Jenny's birthday, then she will have lots of ballons." Since I do not see the usual indicator words, I am looking for guidance to ensure I always pick out eh sufficient condition first. Please advise.

youknowryan wrote:I am not sure which is the sufficient and which is the necessary condition.

The statement:

Jenny will have lots of balloons at her birthday party. There are no balloons yet, so today is not her birthday.


How do I diagram this one? Is it:

BL->BD, contra: ~BD->~BL

OR

BD->BL, contra: ~BL->~BD

I think it is the second one because that would equate to, "If it is Jenny's birthday, then she will have lots of ballons." Since I do not see the usual indicator words, I am looking for guidance to ensure I always pick out eh sufficient condition first. Please advise.

You are correct, it is the second one. To keep the temporal tone '...no balloons YET...' it would be phrased better as "When it is Jenny's birthday she will get lots of balloons at her b-day party."

Yes, it is the second one.

The statement isn't worded very well, since you shift from birthday party to birthday though. Also, it would need to be clearer where the person who is saying there are no balloons is, since her birthday party is both a time and a place. ie he could be down the street.

Audio Technica Guy wrote:Yes, it is the second one.

The statement isn't worded very well, since you shift from birthday party to birthday though. Also, it would need to be clearer where the person who is saying there are no balloons is, since her birthday party is both a time and a place. ie he could be down the street.

THis is one of the responses to a logical reasoning question.... I blame the LSAC.

youknowryan wrote:

Audio Technica Guy wrote:Yes, it is the second one.

The statement isn't worded very well, since you shift from birthday party to birthday though. Also, it would need to be clearer where the person who is saying there are no balloons is, since her birthday party is both a time and a place. ie he could be down the street.

THis is one of the responses to a logical reasoning question.... I blame the LSAC.

Yeah, those responses aren't very technical a lot of times.

youknowryan wrote:

Audio Technica Guy wrote:Yes, it is the second one.

The statement isn't worded very well, since you shift from birthday party to birthday though. Also, it would need to be clearer where the person who is saying there are no balloons is, since her birthday party is both a time and a place. ie he could be down the street.

THis is one of the responses to a logical reasoning question.... I blame the LSAC.

Are you saying that exact phrase was the credited response to a real LSAT question in the context you described? If so, please post the citation reference to the question so I can look it up because that would surprise me a lot. LSAC goes a long way developing and quality controlling questions to avoid such blatant grammar/phrasing errors that can lead to ambiguity about the answer.

Jeffort wrote:

youknowryan wrote:

Audio Technica Guy wrote:Yes, it is the second one.

The statement isn't worded very well, since you shift from birthday party to birthday though. Also, it would need to be clearer where the person who is saying there are no balloons is, since her birthday party is both a time and a place. ie he could be down the street.

THis is one of the responses to a logical reasoning question.... I blame the LSAC.

Are you saying that exact phrase was the credited response to a real LSAT question in the context you described? If so, please post the citation reference to the question so I can look it up because that would surprise me a lot. LSAC goes a long way developing and quality controlling questions to avoid such blatant grammar/phrasing errors that can lead to ambiguity about the answer.

I think he's saying it was in one of the explanations LSAC published. Not in the actual question.

If birthday then balloons.
DONE

This is an actual LSAT answer (B if you're wondering) from a question on P. 407 of the Logical Reasoning Bible. It is also in my parallel reasoning packet from Cambridge LSAT. This is from the LSAC. I have no doubt that it is from an older PT.