SOLUTION: A family of 6 boys and 3 girls. Mother wanted to choose 4 of them to prepare dinner: What is the probability of choosing a boy to prepare tea, a boy to cook, and two girls to proc

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Question 1207851: A family of 6 boys and 3 girls. Mother wanted to choose 4 of them to prepare dinner:
What is the probability of choosing a boy to prepare tea, a boy to cook, and two girls to process
Table?

Answer by ikleyn(52835) About Me  (Show Source):
You can put this solution on YOUR website!
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A family of 6 boys and 3 girls. Mother wanted to choose 4 of them to prepare dinner:
What is the probability of choosing a boy to prepare tea, a boy to cook, and two girls
to process Table?
~~~~~~~~~~~~~~~

The total number of ways to assign jobs  highlight%28randomly%29  is

    9%2A8%2A%28%287%2A6%29%2F2%29 = 9*8*21 = 1512.


(9 ways to fill the first position; 8 ways to fill the second position;
and %287%2A6%29%2F2%29 ways to fill the 3-rd and 4-th positions with possible transposition there).


    +-------------------------------------------+
    |   Now let's calculate the number of ways  |
    |      to assign jobs as described.         |
    +-------------------------------------------+


The number of ways to select one boy from 6 boys to prepare tea is 6.            

The number of ways to select 1 boy from remaining 5 boys to cook is 5.

The number of ways to select 2 girls from 3 girls is 3.


So, the number of ways to form a proper team as described is 6*5*3 = 90.


The probability under the problem's question is

          number of proper ways       90     5
    P = ------------------------- = ----- = ---- = 0.05952  (rounded).    ANSWER
          total number of ways       1512    84



    +---------------------------------------+
    |   Another way  to solve is to write   |
    +---------------------------------------+


    P = %286%2F9%29%2A%285%2F8%29%2A%282%2F7%29 = %281%2F3%29%2A%285%2F4%29%2A%281%2F7%29 = 5%2F84  (the same answer).


Here  6%2F9  is the probability to select one of 6 boys from 9 kids to prepare tea.

      5%2F8  is the probability to select one of remaining 5 boys from remaining 8 kids to cook.

      2%2F7  is the probability to select two of 3 girls from remaining 7 kids to process table.

Solved in two ways, for your better understanding.