find the total no of ways to distribute n things among r people.....

ans is n+r-1 C r-1

ut i dint understand how we get this result?... can you help?

Ways of distributing n things among r people
If n<r then answer will be rPn ways.
(Permutation formula for n from r)(Permutation is used here because same person can again be
selected.
Alternately if n >r, we use nPr ways ( r persons chosen from n)(here also with replacement so
permutation is used).
Regards,
Nirmal Singh
Askiitians Faculty