Tuesday

May 31, 2016
Posted by **Tom** on Thursday, May 24, 2012 at 11:43pm.

*** If you can show work that would be helpful (OPTIONAL)***

THANK YOU VERY MUCH!

- MATH -
**MathMate**, Friday, May 25, 2012 at 9:14amDefine

C(n,r)=n!/(r!(n-r)!)=n choose r

Sample space: C(13,5)=1287

ways to choose 0 boy

=Choose 5 girls out of 7 and 0 boy out of 6

=C(7,5)*C(6,0)=21

ways to choose 1 boy:

=C(7,4)*C(6,1)=210

ways to choose 2 boys:

=C(7,3)*C(6,2)=525

ways to choose 3 boys:

=C(7,2)*C(6,3)=420

ways to choose 4 boys:

=C(7,1)*C(6,4)=105

ways to choose 5 boys:

=C(7,0)*C(6,5)=6

If you add them all up, they will total 1287 as required.

Now make appropriate sums according to requirements and calculate probability.