<PRE><B>Question 356433</B>
7 boys and 3 girls
nCr=combination of n things taken r at a time.
a)
(3C3 * 7C2)/10C5
=1*21/252
=1/12 probability that all 3 girls will be picked.
.
b)
7C5/10C5
=21/252
=1/12 probablilty that none of the girls will be picked.
.
c)
(3C2 * 7C3)/10C5
=3*35/252
=105/252
=5/12 probability of 2 girls getting picked.
.
Ed</PRE>