Results 1 to 3 of 3

Math Help - numbers of elements in a set

  1. #1
    Senior Member
    Joined
    Jan 2009
    Posts
    296

    numbers of elements in a set

    For this |A| is the number of elements in A.

    So we are given:

    |A|=24, |B|=21, |AUB|=37, |A intersect C|=11, |B-C|=10 and |C-B|=12

    We need to find:

    a)|B-A|

    b)|BUC|

    c) |C|


    I know that we can use |AUB| =|A|+|B|-|A intersect B| to find how many elements in A intersect B, but the subtraction part is throwing me off.
    Any ideas? Thank you.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Apr 2005
    Posts
    16,004
    Thanks
    1660
    Quote Originally Posted by zhupolongjoe View Post
    For this |A| is the number of elements in A.

    So we are given:

    |A|=24, |B|=21, |AUB|=37, |A intersect C|=11, |B-C|=10 and |C-B|=12

    We need to find:

    a)|B-A|

    b)|BUC|

    c) |C|


    I know that we can use |AUB| =|A|+|B|-|A intersect B| to find how many elements in A intersect B, but the subtraction part is throwing me off.
    Any ideas? Thank you.
    A-B= A\cup B- A\cap B
    |A-B= |A\cup B|- |A\cap B|
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member
    Joined
    Jan 2009
    Posts
    296
    Ok, so |A-B|=37-8=29

    How do we get B-A from that, is it just like 37-29?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: December 10th 2011, 06:40 PM
  2. Replies: 8
    Last Post: November 27th 2011, 10:18 PM
  3. [SOLVED] Why are these not elements of W
    Posted in the Advanced Algebra Forum
    Replies: 12
    Last Post: October 22nd 2011, 03:02 PM
  4. Replies: 0
    Last Post: September 15th 2009, 09:27 PM
  5. Elements
    Posted in the Discrete Math Forum
    Replies: 2
    Last Post: December 9th 2008, 04:52 PM

Search Tags


/mathhelpforum @mathhelpforum