Answer
1140 non-negative solutions
Work Step by Step
Given that
x1 + x2 + x3 + x4 = 17
and x1$\geq$ 0, x2$\geq$ 0, x3$\geq$ 0, x4$\geq$ 0
Number of ways is given by $C$(n+r-1,r)
here n=4 , r=17
$C$(20,17) = 1140 non-negative solutions exist for x1 + x2 + x3 + x4 = 17
