Philosophy Logic question! Help me ...?

Question

The question is called Figure Eights. Its from my Logic class. It gives you 3 facts and 2 question!

1. If Julie goes ice skating, then her friend Jeff will go ice skating.

2. If Jeff goes ice skating, then his sister Angie will go ice skating.

3. Jeff will not go ice skating.

Will Julie go ice skating?

Will Angie go ice skating?

How would you answer those 2 questions from the above statements. We have three answer options: Yes, No, Not enough information! And then you have to explain your reasoning.

HELP!

Answer 1

no to both, as Jeff is not going, then his sister Angie will not, but if Julie went, then all three would go.

Answer 2

Jeff is like you...he needs help buttering his bread. Leave ice skating to the bigger kids.

Answer 3

the answer to both questions is NO.  Break the question up.

1. If Julie goes ice skating, then her friend Jeff will go ice skating.

       Jeff will not go ice skating.  ANd if your assuming number one is true, than you have to assume that Julie doesn't go ice skating either.  

Answer 4

Cheese Bob.  You say Julie WILL go ice skating regardless of Jeff's choice.  Not true.  The first statement clearly states IF she goes...

So if Jeff doesn't go then Julie didn't go, because if she did go skating then Jeff would have gone.  And Angie won't go because Jeff is not going.

The first answer is right.  Give her best answer.

Answer 5

Not enough info to tell.  

The facts don't tell you what happens if Jeff does not go skating.

Consider: Perhaps Julie & Angie will go skating regardless of what Jeff does.

Answer 6

Answer to #1:    Not Enough Info

   While it lists stipulations for Jeff or Angie to go skating, it lists none for Julie

Answer to #2:        No

  If Angie will only go skating because Jeff goes, and Jeff does not go, then neither will she.

Answer 7

In order:

1. So we assume that Jeff will follow Julie, if she goes, he will go, therefore, if she doesn't go, he will not go.

2. Angie will go if Jeff goes... that's about it

3. Since Jeff is not going, we can say his not going will cause Angie to not go. Why isn't he going? Well from this information, it is because Julie did not go.

Answer 8

there's never enough information.  

Answer 9

The answer to the first question is "no". It's an example of modus tollens. That Jeff doesn't go ice skating means Julie won't either, as per the given criteria.

However, his sister Angie could still decide to go anyway. Jeff going ice-skating is only one condition for Angie's decision to go as well, not necessarily the only one. That is, it might be, but we don't have enough information. If the sentence were "ONLY if Jeff goes ice skating will Angie go ice skating" the answer would be different. In that case, it would be "no" as well.

So, here are my answers:

1. No.

2. Not enough information.

Hope that helps somewhat.

By the way, whoever gave this answer thumbs down is a moron.

Answer 10

Will Julie Iceskate: Yes, because her condition is that she skates, regardless of what Jeff does. Her act is independent of his choice.

Will Angie go Skating: No, because her decision lies in the decision of Jeff, where if he refueses, so will she.

Both statements seem to produce absolutes, so if one doesn't go, the other absolutely doesn't go either (since they ONLY go if the other goes). Any other conditions would render the "going" part null.

You can argue that Jeff HAS to go if Angie does, but that just complicates things then. Since Angie is supposed to be the independent variable, why should her decision be dependent on Jeff's?

Answer 11

it might help to list out all the possibilities.

for the first question, julie could go or not go ice skating are the two possibilities. possibility 1: if julie goes, then jeff goes. possibility 2: if julie does not go, jeff could go or not go. given statement 3, you know jeff did not go. so it must be the second possibility that that julie does not go.

for the second question, again list the possibilities. possibility 1: jeff goes, then angie goes. possibility 2: jeff don't go, and angie may or may not go. from given statement 3, you know that jeff does not go. so that eliminates the first possibility. that leaves angie may or may not go, so there is not enough information to determine whether angie goes ice skating or not.

the answers are no, not enough info.