A guy own 10 white toy bulls, 14 yellow toy bulls, and 8 black toy bulls.
If he is blindfolded, and puts 11 bulls in one bag, and 11 in another bag, what is the chance of a yellow bull being in bag 1, and the chance of a black bull being in both bag 1 and 2?
They're are 10 leftover bulls. What is the chance of a white bull being in the group of leftover bulls?
P[at least 1 yellow bull in bag 1]=1−P[no yellow bulls in bag 1]=1−10∑w=3(10w)(811−w)(3211)=206719206770
I'll post #2 when I figure it out
P[white bull in group of leftovers]=1−P[all white bulls in bag 1 or bag 2]=(think of bag 1 and bag 2 as one big bag here)1−12∑y=4 (14y)(812−y)(3222)=24563692481240
P[at least 1 black bull in each bag]=1−P[no black bull in bag 1 or no black bull in bag 2 or both]=1−P[no black bull in bag 1]−P[no black bull in bag 2]+P[no black bull in either bag]
As the problem is symmetric w/respect to the bagsP[no black bull in bag 1]=P[no black bull in bag 2]P[no black bull in bag 1]=10∑w=0 (10w)(1411−w)(3211)=2261116870
P[no black bull in either bag]=2∑w=0 (10w)(142−w)(3210)=1233740
P[at least 1 black bull in both bags]=1−22261116870+1233740=224697233740
.