5 prefects are to be chosen from 6 boys and 4 girls.in how many ways can this be done if

a)all the prefects are boys

b)there are at least two girls

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- Jun 3rd 2010, 02:29 PMcantcountpermutation and combination question...please help!
5 prefects are to be chosen from 6 boys and 4 girls.in how many ways can this be done if

a)all the prefects are boys

b)there are at least two girls - Jun 3rd 2010, 03:10 PMgalactusQuote:

a)all the prefects are boys

Quote:

b)there are at least two girls

2 girls and 3 boys, 3 girls and 2 boys, 4 girls and 1 boy.

$\displaystyle \binom{4}{2}\binom{6}{3}+\binom{4}{3}\binom{6}{2}+ \binom{4}{4}\binom{6}{1}$