Question
Question: The no. of non-negative integral solutions of x + y + z + w ≤ 40 is...
The no. of non-negative integral solutions of x + y + z + w ≤ 40 is
A
44C3
B
40C3
C
40C4
D
44C4
Answer
44C4
Explanation
Solution
Let λ be a variable which is equal to 40 - (x + y + z + w).
x + y + z + w + λ = 40 = 44C4.