As i got the contrapositive of this statement, how does e) necessarily follows from this? [closed]












1














An electronic circuit contains three light bulbs, X, Y and Z, which are each either on or off at
any particular time. It is known that if bulb X is off or bulb Y is on, then bulb Z is on.
Which one of these statements necessarily follows from this?



A. If bulb Z is on, then bulb X is off or bulb Y is on.



B. If bulb Z is on, then bulb X is on and bulb Y is off.



C. If bulb Z is on, then bulb X is on or bulb Y is on.



D. If bulb Z is off, then bulb X is off and bulb Y is off.



E. If bulb Z is off, then bulb X is on or bulb Y is off.



F. If bulb Z is off, then bulb X is on and bulb Y is on.





The contrapositive of the given statement is If bulb Z is off, then bulb X is on and bulb Y is off. However, apparently, there is no such choice in the given choices.










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closed as off-topic by José Carlos Santos, Holo, metamorphy, Abcd, user91500 Dec 29 '18 at 10:24


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, Holo, metamorphy, Abcd, user91500

If this question can be reworded to fit the rules in the help center, please edit the question.













  • Did you try to put this into a logical expression?
    – Bram28
    Dec 28 '18 at 14:35










  • actly the answer is e,but i dont know why
    – Kevin
    Dec 28 '18 at 14:38






  • 1




    @Kevin You correctly found the the contrapositive ....now think a little about what that says ... and you'll see how e) logically follows from that. That is, answer e) is not equivalent to the original statement, but it does logically follow from it
    – Bram28
    Dec 28 '18 at 14:46










  • @Bram28 im sorry, could u please be more detail oriented on how does it follow from it
    – Kevin
    Dec 28 '18 at 14:46












  • @Kevin remember the logical "or" is inclusive. So, if I tell you that snow is white and grass is green, does it follow (in logic) that snow is white or grass is green?
    – Bram28
    Dec 28 '18 at 14:46


















1














An electronic circuit contains three light bulbs, X, Y and Z, which are each either on or off at
any particular time. It is known that if bulb X is off or bulb Y is on, then bulb Z is on.
Which one of these statements necessarily follows from this?



A. If bulb Z is on, then bulb X is off or bulb Y is on.



B. If bulb Z is on, then bulb X is on and bulb Y is off.



C. If bulb Z is on, then bulb X is on or bulb Y is on.



D. If bulb Z is off, then bulb X is off and bulb Y is off.



E. If bulb Z is off, then bulb X is on or bulb Y is off.



F. If bulb Z is off, then bulb X is on and bulb Y is on.





The contrapositive of the given statement is If bulb Z is off, then bulb X is on and bulb Y is off. However, apparently, there is no such choice in the given choices.










share|cite|improve this question















closed as off-topic by José Carlos Santos, Holo, metamorphy, Abcd, user91500 Dec 29 '18 at 10:24


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, Holo, metamorphy, Abcd, user91500

If this question can be reworded to fit the rules in the help center, please edit the question.













  • Did you try to put this into a logical expression?
    – Bram28
    Dec 28 '18 at 14:35










  • actly the answer is e,but i dont know why
    – Kevin
    Dec 28 '18 at 14:38






  • 1




    @Kevin You correctly found the the contrapositive ....now think a little about what that says ... and you'll see how e) logically follows from that. That is, answer e) is not equivalent to the original statement, but it does logically follow from it
    – Bram28
    Dec 28 '18 at 14:46










  • @Bram28 im sorry, could u please be more detail oriented on how does it follow from it
    – Kevin
    Dec 28 '18 at 14:46












  • @Kevin remember the logical "or" is inclusive. So, if I tell you that snow is white and grass is green, does it follow (in logic) that snow is white or grass is green?
    – Bram28
    Dec 28 '18 at 14:46
















1












1








1







An electronic circuit contains three light bulbs, X, Y and Z, which are each either on or off at
any particular time. It is known that if bulb X is off or bulb Y is on, then bulb Z is on.
Which one of these statements necessarily follows from this?



A. If bulb Z is on, then bulb X is off or bulb Y is on.



B. If bulb Z is on, then bulb X is on and bulb Y is off.



C. If bulb Z is on, then bulb X is on or bulb Y is on.



D. If bulb Z is off, then bulb X is off and bulb Y is off.



E. If bulb Z is off, then bulb X is on or bulb Y is off.



F. If bulb Z is off, then bulb X is on and bulb Y is on.





The contrapositive of the given statement is If bulb Z is off, then bulb X is on and bulb Y is off. However, apparently, there is no such choice in the given choices.










share|cite|improve this question















An electronic circuit contains three light bulbs, X, Y and Z, which are each either on or off at
any particular time. It is known that if bulb X is off or bulb Y is on, then bulb Z is on.
Which one of these statements necessarily follows from this?



A. If bulb Z is on, then bulb X is off or bulb Y is on.



B. If bulb Z is on, then bulb X is on and bulb Y is off.



C. If bulb Z is on, then bulb X is on or bulb Y is on.



D. If bulb Z is off, then bulb X is off and bulb Y is off.



E. If bulb Z is off, then bulb X is on or bulb Y is off.



F. If bulb Z is off, then bulb X is on and bulb Y is on.





The contrapositive of the given statement is If bulb Z is off, then bulb X is on and bulb Y is off. However, apparently, there is no such choice in the given choices.







propositional-calculus






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edited Jan 2 at 13:39







Kevin

















asked Dec 28 '18 at 14:28









KevinKevin

143




143




closed as off-topic by José Carlos Santos, Holo, metamorphy, Abcd, user91500 Dec 29 '18 at 10:24


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, Holo, metamorphy, Abcd, user91500

If this question can be reworded to fit the rules in the help center, please edit the question.




closed as off-topic by José Carlos Santos, Holo, metamorphy, Abcd, user91500 Dec 29 '18 at 10:24


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, Holo, metamorphy, Abcd, user91500

If this question can be reworded to fit the rules in the help center, please edit the question.












  • Did you try to put this into a logical expression?
    – Bram28
    Dec 28 '18 at 14:35










  • actly the answer is e,but i dont know why
    – Kevin
    Dec 28 '18 at 14:38






  • 1




    @Kevin You correctly found the the contrapositive ....now think a little about what that says ... and you'll see how e) logically follows from that. That is, answer e) is not equivalent to the original statement, but it does logically follow from it
    – Bram28
    Dec 28 '18 at 14:46










  • @Bram28 im sorry, could u please be more detail oriented on how does it follow from it
    – Kevin
    Dec 28 '18 at 14:46












  • @Kevin remember the logical "or" is inclusive. So, if I tell you that snow is white and grass is green, does it follow (in logic) that snow is white or grass is green?
    – Bram28
    Dec 28 '18 at 14:46




















  • Did you try to put this into a logical expression?
    – Bram28
    Dec 28 '18 at 14:35










  • actly the answer is e,but i dont know why
    – Kevin
    Dec 28 '18 at 14:38






  • 1




    @Kevin You correctly found the the contrapositive ....now think a little about what that says ... and you'll see how e) logically follows from that. That is, answer e) is not equivalent to the original statement, but it does logically follow from it
    – Bram28
    Dec 28 '18 at 14:46










  • @Bram28 im sorry, could u please be more detail oriented on how does it follow from it
    – Kevin
    Dec 28 '18 at 14:46












  • @Kevin remember the logical "or" is inclusive. So, if I tell you that snow is white and grass is green, does it follow (in logic) that snow is white or grass is green?
    – Bram28
    Dec 28 '18 at 14:46


















Did you try to put this into a logical expression?
– Bram28
Dec 28 '18 at 14:35




Did you try to put this into a logical expression?
– Bram28
Dec 28 '18 at 14:35












actly the answer is e,but i dont know why
– Kevin
Dec 28 '18 at 14:38




actly the answer is e,but i dont know why
– Kevin
Dec 28 '18 at 14:38




1




1




@Kevin You correctly found the the contrapositive ....now think a little about what that says ... and you'll see how e) logically follows from that. That is, answer e) is not equivalent to the original statement, but it does logically follow from it
– Bram28
Dec 28 '18 at 14:46




@Kevin You correctly found the the contrapositive ....now think a little about what that says ... and you'll see how e) logically follows from that. That is, answer e) is not equivalent to the original statement, but it does logically follow from it
– Bram28
Dec 28 '18 at 14:46












@Bram28 im sorry, could u please be more detail oriented on how does it follow from it
– Kevin
Dec 28 '18 at 14:46






@Bram28 im sorry, could u please be more detail oriented on how does it follow from it
– Kevin
Dec 28 '18 at 14:46














@Kevin remember the logical "or" is inclusive. So, if I tell you that snow is white and grass is green, does it follow (in logic) that snow is white or grass is green?
– Bram28
Dec 28 '18 at 14:46






@Kevin remember the logical "or" is inclusive. So, if I tell you that snow is white and grass is green, does it follow (in logic) that snow is white or grass is green?
– Bram28
Dec 28 '18 at 14:46












1 Answer
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From the comments, I gather you correctly found the contrapositive (you should really add that to your post ... in general, you should always add your work to your post). So, that is:



If Z is off, then X is on and Y is off



Now, this is almost the same as answer e) ... except in e) you have an 'or' rather than an 'and'



But, remember that in logic the 'or' is inclusive. So, if it is true that 'P and Q', then it follows that 'P or Q'.



Likewise, if Z is off, we know X is on and Y is off. But then it is also true that X is on or Y is off. So, if Z is off, then X is on or Y is off



So, the answer is e). e) is not logically equivalent to the original statement but, as we saw, it does logically follow from it, and that is what the question asked.






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    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    1














    From the comments, I gather you correctly found the contrapositive (you should really add that to your post ... in general, you should always add your work to your post). So, that is:



    If Z is off, then X is on and Y is off



    Now, this is almost the same as answer e) ... except in e) you have an 'or' rather than an 'and'



    But, remember that in logic the 'or' is inclusive. So, if it is true that 'P and Q', then it follows that 'P or Q'.



    Likewise, if Z is off, we know X is on and Y is off. But then it is also true that X is on or Y is off. So, if Z is off, then X is on or Y is off



    So, the answer is e). e) is not logically equivalent to the original statement but, as we saw, it does logically follow from it, and that is what the question asked.






    share|cite|improve this answer


























      1














      From the comments, I gather you correctly found the contrapositive (you should really add that to your post ... in general, you should always add your work to your post). So, that is:



      If Z is off, then X is on and Y is off



      Now, this is almost the same as answer e) ... except in e) you have an 'or' rather than an 'and'



      But, remember that in logic the 'or' is inclusive. So, if it is true that 'P and Q', then it follows that 'P or Q'.



      Likewise, if Z is off, we know X is on and Y is off. But then it is also true that X is on or Y is off. So, if Z is off, then X is on or Y is off



      So, the answer is e). e) is not logically equivalent to the original statement but, as we saw, it does logically follow from it, and that is what the question asked.






      share|cite|improve this answer
























        1












        1








        1






        From the comments, I gather you correctly found the contrapositive (you should really add that to your post ... in general, you should always add your work to your post). So, that is:



        If Z is off, then X is on and Y is off



        Now, this is almost the same as answer e) ... except in e) you have an 'or' rather than an 'and'



        But, remember that in logic the 'or' is inclusive. So, if it is true that 'P and Q', then it follows that 'P or Q'.



        Likewise, if Z is off, we know X is on and Y is off. But then it is also true that X is on or Y is off. So, if Z is off, then X is on or Y is off



        So, the answer is e). e) is not logically equivalent to the original statement but, as we saw, it does logically follow from it, and that is what the question asked.






        share|cite|improve this answer












        From the comments, I gather you correctly found the contrapositive (you should really add that to your post ... in general, you should always add your work to your post). So, that is:



        If Z is off, then X is on and Y is off



        Now, this is almost the same as answer e) ... except in e) you have an 'or' rather than an 'and'



        But, remember that in logic the 'or' is inclusive. So, if it is true that 'P and Q', then it follows that 'P or Q'.



        Likewise, if Z is off, we know X is on and Y is off. But then it is also true that X is on or Y is off. So, if Z is off, then X is on or Y is off



        So, the answer is e). e) is not logically equivalent to the original statement but, as we saw, it does logically follow from it, and that is what the question asked.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Dec 28 '18 at 14:53









        Bram28Bram28

        60.3k44590




        60.3k44590















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