The number of ways in which 3 children can distribute 10 tickets out of 15 consecutively numbered tickets among themselves such that they get consecutive blocks of 5, 3 and 2 tickets is
8C3×(3!)2
Problem is same as arranging 8 things out of which 5 identical i.e. 8!5! which gives total number of ways of selecting block and distributing them away to 3 children =8!5!×3!