data management

For MAMMALS, find the munber of:
a) 7-letter words
b) 7-letter word beggining with MA
c) 4-letter words
i) all letters different
ii) 2 letters same,2 different
iii) 2 pairs same letters
iv) 3 letters same

asked by Lisa
  1. I am not doing the problem for you but perhaps I can give you an idea.
    Let's see. I have to work with
    M M M A A L S
    If all letters were different the answer would be 7!, but they are not.

    Let me try a simpler example
    Say
    A A B B
    A B A B
    A B B A
    B A A B
    B B A A
    B A B A Hmm six of them, not 4!
    Looks like permutations of 4 items divided by permutations of 2 As divided by permutations of 2 Bs
    4!/(2!*2!) = 4*3*2 /( 2*2) = 6
    Let's try it with 3 As and 1 B
    A A A B
    A A B A
    A B A A
    B A A A Is that 4!/(3!*1!) ?
    4*3*2 /(3*2*1) = 4, sure enough.

    posted by Damon

Respond to this Question

First Name

Your Response

Similar Questions

  1. Data Management

    For PLANETS, find the number of : 4-letter words which must include a L and A For MAMMALS, find the munber of: a) 7-letter words b) 7-letter word beggining with MA c) 4-letter words i) all letters different ii) 2 letters same,2
  2. History

    Even though I asked this before, can you please help me with this and yes it's a crossword puzzle. My teacher gave us clues that don't really help at all and I've looked back in my textbook but I can't find the words for each
  3. Listening

    I need to find the answer to this riddle. I followed the directions but didn't come up with anything I see that makes sense. Can anyone help please? Thanks! What word is spelled after following these directions? 1. Write the words
  4. Maths

    A word made by writing the seven letters used to spell "EXAMPLE" in some order. Find how many different 'words' are possible in each of the following cases. a) The first and the last letter are each "E" b) The two letters "E" are
  5. Math

    The average length of the eight words Betty was asked to spell was 9 letters. The first seven words had the following lengths: 8 letters, 9 letters, 6 letters, 10 letters, 7 letters, 9 letters, and 11 letters. What was the length
  6. Geometry

    Ok i have a crossward puzzle and don't know some of the vocab. Here is what i have : 1)Two endpoints and all the points between them. (7 letters long and the 4th letter is M) 2)The point where the X-axis and Y-axis meet.(6 letters
  7. Geography

    im doing this geography crossword. could you help me figure out what these words are?:) its 5 letters.. organic material that improves soil fertility the last letter is S ..and this one? its 14 letters.. Ability of land to be used
  8. Socials

    I am doing a crossword puzzle and I need help on two words. The first one is: Royal documents that set out terms and permission.( 3 words) There are 15 letters and the 7th letter is S. I thought it would be LettersPatent, but that
  9. Socials Crosswords

    Canada and the Twenties... New form of signage? It's 4 letters, and the second letter is E. Leader in the Winnipeg General Strike? 3 letters, and the last letter is U. Canada becomes involved in this international group in the
  10. cross word puzzle

    This is for tomorrow and i'm in trouble with this puzzle, please help:ACROSS 9 letters and start with (au)the hint is groups of people who watch or listen to a show, speech, or other performance. Down:It starts off with (aw) and

More Similar Questions