Permutation and Combination problem : In how many ways can Rs. 16 be divided into 4 person when none of them get ... Permutation and Combination problem : 
Problem : In how many ways can Rs. 16 be divided into 4 person when none of them get less than Rs. 3 ? 
I have this : The number of ways of distributing $n$ things all alike into $r$ different groups is $^{n+r-1}C_{r-1}$ lots , no lots being blank: 
Coefficient of $x^n $ in $(1+x+x^2+.....)^r$
I am unable to understand how to use this case in the given problem. Request you to please help me on this and elaborate a bit .. will greatful to you... Thanks...

What you want is, how many ways are there to write
$$\{1, \ldots, 16\} = A_1 \dot{\cup} A_2 \dot\cup A_3 \dot\cup A_4$$
Under the constraint, that $|A_i| \geq 3 \quad \forall\ i$.
Did I understand that correctly?
