AIEEE 2002 Math Solved Paper

Here in this expansion (1+x)p+q
The general term =Tr+1=‌p+qCr.(x)r
∴xp will be present in the term =p+qCp⋅(x)p
So coefficient of xp=‌p+qCp
And xq will be present in the term =‌p+qCq⋅(x)q
∴ coefficient of xq=p+qCq
We know ‌nCr=‌nCn−r
∴p+qCq=p+qC(p+q)−q=p+qCp
So coefficients of xp and xq are equal.