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the questions i have to ask i believe have a similar process which is why i have grouped them together:

  1. Sets P and Q; |P|= 6, |Q|= 15 and |P 'AND' Q| = 5; what's |Q\P|

    I know the answers is 10, I'm just not sure that my method was correct as i was trying to figure out the process from the answer; at first i did 15-5 then 15-6+1 but I'm sure its incorrect

  2. each set X and Y contain 19 elements, then the maximum number of elements in the set

    (X 'OR' Y)\Y (answer 19)

  3. each set P and Q contains 40 elements; the maximum number of elements in the set

    P 'OR' (Q\P) (answer 80)

If anyone can help that would be appreciated; i think i am confusing myself by trying to think of the elements themselves rather than how many of them there are and I am not sure how to adapt counting principles to these questions.

  • 0
    Have you tried drawing Venn diagrams?2012-11-18
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    Thanks for your suggestion :)! I tried for one question but I'm not particularly good at them; these questions are multiple choice for an exam that we have limited time on so i was wondering more-so if there was a quicker way to answer the questions rather than Venn diagrams ;)2012-11-18
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    I think Venn diagrams are pretty quick. I submit the answer by @Andre as evidence.2012-11-18
  • 0
    No worries, thanks ;)2012-11-18

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