Wiskundeforum

children are standing in a line outside a ticket window . of them have one rupee

coin each and have two rupee coin each and the entry ticket is priced Rupee 1.

if all arrangements of 2o children are equally likely ,

find probability that 10th child will be first to wait for change

P = P(c1=1R en c2=1R en ... en c9=1R en c10=2R) = ...

Thanks moderator got it