Question
Question: Number of non negative integral solutions of the equation a+b+c = 6 is...
Number of non negative integral solutions of the equation a+b+c = 6 is
A
28
B
32
C
36
D
56
Answer
28
Explanation
Solution
Required solution
= Coefficient of x6 in (1+x+x2 + ....)3
= Coefficient of x6 in (1 – x)-3
= 3+6 – 1C6
= 8C6 = 28