Results 1 to 3 of 3

Math Help - i need help with this combination/probability thingy :(

  1. #1
    Newbie
    Joined
    Nov 2009
    Posts
    2

    i need help with this combination/probability thingy :(

    i know how to solve these questions, but i'm supposed to put them into categories but i don't know what kind of categories to put them into the teacher also says to write what these problems have in common and why you multiply to get the answers but i am very stupid so i don't know.

    1. A deli has five types of meat, two types of cheese, and three types of bread. How many different sandwiches consisting of one type of meat, one type of cheese, and one type of bread, does the deli serve?

    2. In a six-team division of a baseball league, each team plays each other 9 times. How many games will be played in the division?

    3. A standard 52-card deck has four suits (hearts, clubs, diamonds, and spades) with 13 cards in each suit. How many five-card hands consist of four diamonds and one spade?

    4. John has five shirts, three ties, and seven suits. How many possible outfits consisting of one shirt, one tie, and one suit does he have?

    5. A locker combination system uses three digits from 0 to 9. How many different three-digit combinations with no digit repeated are possible?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Prove It's Avatar
    Joined
    Aug 2008
    Posts
    11,492
    Thanks
    1391
    Quote Originally Posted by imverystupid View Post
    i know how to solve these questions, but i'm supposed to put them into categories but i don't know what kind of categories to put them into the teacher also says to write what these problems have in common and why you multiply to get the answers but i am very stupid so i don't know.

    1. A deli has five types of meat, two types of cheese, and three types of bread. How many different sandwiches consisting of one type of meat, one type of cheese, and one type of bread, does the deli serve?

    2. In a six-team division of a baseball league, each team plays each other 9 times. How many games will be played in the division?

    3. A standard 52-card deck has four suits (hearts, clubs, diamonds, and spades) with 13 cards in each suit. How many five-card hands consist of four diamonds and one spade?

    4. John has five shirts, three ties, and seven suits. How many possible outfits consisting of one shirt, one tie, and one suit does he have?

    5. A locker combination system uses three digits from 0 to 9. How many different three-digit combinations with no digit repeated are possible?
    Use tree diagrams to determine all the possible combinations.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,707
    Thanks
    626
    Hello, imverystupid!

    i'm supposed to put these into categories,
    but i don't know what kind of categories to put them into.

    I don't know the categories either . . . can't help you.

    The teacher also says to write what these problems have in common

    They're "counting problems"?

    and why you multiply to get the answers.

    Because of the "Fundamental Theorem of Counting"?

    1. A deli has 5 types of meat, 2 types of cheese, and 3 types of bread.
    How many different sandwiches consist of 1 meat, 1 cheese, and 1 bread,?
    This is a "fundamental" problem.

    5\times 2 \times 3 \:=\:30 possible sandwiches.




    2. In a six-team division of a baseball league, each team plays each other 9 times.
    How many games will be played in the division?
    This is "combinations".

    The 6 teams can be paired off in: . _6C_2 \:=\:{6\choose2} \:=\:\frac{6!}{2!\,4!} \:=\:15 ways.

    This pairing will be repeated 9 times.

    There will be: . 9 \times 15 \:=\:135 games.




    3. A standard 52-card deck has four suits (hearts, clubs, diamonds, and spades)
    with 13 cards in each suit. How many five-card hands consist of four Diamonds and one Spade?
    This is "combinations".

    There are: . _{13}C_4 \;=\;\frac{13!}{4!\,9!} \;=\;{13\choose4} \;=\;715 ways to get 4 \diamondsuit s
    There are: . _{13}C_1 \;=\;{13\choose1} \;=\;13 ways to get one \spadesuit

    Therefore, there are: . 715 \times 13 \:=\:9295 hands with 4 \diamondsuit \text{s and 1 }\spadesuit.




    4. John has five shirts, three ties, and seven suits.
    How many possible outfits have 1 shirt, 1 tie, and 1 suit?
    Another "fundamental" problem.

    He has: . 5 \times 3 \times 7 \:=\:105 possible outfits.




    5. A locker combination system uses three digits from 0 to 9.
    How many different three-digit combinations with no digit repeated are possible?
    Yet another "fundamental" problem.

    The 1st digit has 10 choices.
    The 2nd digit has 9 choices.
    The 3rd digit has 8 choices.

    Therefore, there are: . 10 \times 9 \times 8 \:=\:720 possible combinations.

    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. probability with combination
    Posted in the Statistics Forum
    Replies: 1
    Last Post: December 16th 2011, 06:31 AM
  2. A vector equation thingy
    Posted in the Calculus Forum
    Replies: 2
    Last Post: May 20th 2010, 05:47 AM
  3. Please help on 5th grade prime thingy
    Posted in the Algebra Forum
    Replies: 5
    Last Post: September 10th 2009, 03:52 PM
  4. graph thingy
    Posted in the Algebra Forum
    Replies: 3
    Last Post: July 30th 2009, 11:06 PM
  5. Combination Probability
    Posted in the Statistics Forum
    Replies: 1
    Last Post: March 25th 2007, 07:13 PM

Search Tags


/mathhelpforum @mathhelpforum