Division and Distribution of Identical Objects
Case 1
Number of ways in which n identical things can be divided into r groups, if blank groups are allowed (here groups are numbered, i.e., distinct)
= Number of ways in which n identical things can be distributed among r persons, each one of them can receive 0,1,2 or more items
= (n+r-1)C(r-1)
can we do like this here girls =2 lets these two girls are two groups , 10 roses ,
so (10 + 2 -1) C(2-1) = 11
and so on