The number of positive integral solutions of 2x1+3x2+4x3+5x4=25 is?

Question

Options
A) 20
B) 22
C) 23
D) none of these

Answer 1

some may repeat and some complex but the max is:
1 solution for m x + b = 0
2 solutions for a x^2 + b x + c = 0
3 solutions for a x^3 + b x^2 + c x + d = 0
4 solutions for a x^4 + b x^3 .......

Answer 2

Didnt understand
This sum is from permutations and combinations
Plse help

Answer 3

I didn't understand
Plse help me

Answer 4

Answer pls