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Thread: [SOLVED] permutations 2

  1. #1
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    [SOLVED] permutations 2

    a) How many permutations are there of the letters in the word baseball?

    my thinking \frac{8}{2!2!2!}=5040

    b) How many begin with the letter a?

    c) How many end with the letter e?
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  2. #2
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    Quote Originally Posted by william View Post
    a) How many permutations are there of the letters in the word baseball?

    my thinking \frac{8}{2!2!2!}=5040

    b) How many begin with the letter a?

    c) How many end with the letter e?

    (b) There are 2 arrangements that will begin with the letter a . Thus , 7!/(2!2!)


    (c)ONly 1 arrangement will end with e . Thus , 7!/(2!2!2!)
    Last edited by mathaddict; Feb 12th 2009 at 05:35 AM. Reason: MIstakes !
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  3. #3
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    Hello, William!

    a) How many permutations are there of the letters in the word BASEBALL?

    My thinking: \frac{8}{2!2!2!}\:=\:5040 . . . . Right!

    b) How many begin with the letter A?

    Place one of the A's in front: . A\:\_\:\_\:\_\:\_\:\_\:\_\:\_

    Then the other seven letters \{A,B,B,E,L,L,S\}
    . . can be arranged in \frac{7!}{2!2!} \:=\:1260 ways.



    c) How many end with the letter E?

    Place the E on the end: . \_\:\_\:\_\:\_\:\_\:\_\:\_\:E

    Then the other seven letters \{A,A,B,B,L,L,S\}
    . . can be arranged in \frac{7!}{2!2!2!} \:=\:630 ways.

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