TS EAMCET 11-Sep-2020 Shift 1 Solved Paper

It is given that, x,y,z≥−1 and w≥1
Now, let ‌‌a=x+1≥0
b=y+1≥0
c=z+1≥0
d=w−1≥0
∴ The given equation x+y+z+w=25 reduce to
⇒‌‌a+b+c+d=27
∴ The number of required solution is same as the number of non-negative integral solutions of equation
a+b+c+d=27
and it is equal to ‌27+4−1C4−1=‌30C3