awesome as always jagdish bhaiya!!
here is my take on it.
i let x = a + b.
y = b + c.
z = c + a.
we get,
1/(y+1) + 1(z+1) < o equal to x/(x+1).
or, on croos multiplication,
x + y + z + 2 < or equal to xyz.
2(a+b+c) + 2 < or equal to (a+b)(b+c)(c+a) = a^2b + b^2a + c^2a + a^2c + b^2c + c^2b + 2abc.
we cancel out 2abc and 2.
then we add 3 to both the sides.
a^2b + a^2c + 1 > or equal to 3a by AM - GM.
similalrly for all and thenn add.
2(a+b+c) + 3 < or equal to 3(a+b+c).
or a + b + c > or equal to 3.
which is evidient from am - gm since abc = 1.