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Homework Help: Can you check to see if I got all these sets right?

  1. Jan 30, 2008 #1
    1. The problem statement, all variables and given/known data

    Supppose that vechiles taking a particular free way exit can turn right (r), left (l), or go straight (s). Consider observing the direction for each of three sucessive vechiles.

    3. The attempt at a solution

    So there is a total of 3^3 = 27 possiblities right.

    a. list all outcomes in the event A that all three vechiles go in the same direction:
    A = {rrr,lll,sss}

    b. List all outcomes in the event B that all three vechiles take different directions:
    B = {rls,rsl,srl,slr,lsr,lrs}

    c. List all outcomes in event C that exactly tow of the three vchiles turn right.

    C = {rrs,rrl,rsr,rlr,srr,lrr}

    d. List all outcomes in the event D that exactly two vechiles turn the same directoin:
    D = {rrs,rrl,rsr,rlr,srr,lrr,
    lls, llr, lsl, lrl, sll, rll, ssl, ssr, sls, srs, lss, rss };

    e. List all D';
    D' = {rrr,lll,sss,rls, rsl, srl, slr, lsr, lrs, rrs, rrl, rsr, rlr, srr, lrr}
    C U D = { rrs, rrl, rsr, rlr, srr, lrr, lls, llr, lsl, lrl , sll, rll, ssl, ssr, sls, srs, lss, rss};
    C intersect D = { rrs, rrl, rsr, rlr, srr, lrr};

    To be a set, you can't have duplications right? so C U D, because C is a subset of D, that means I wouldn't rewrite the elements if D already has them correct? Like in C U D, I only wrote D.

  2. jcsd
  3. Jan 31, 2008 #2


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