Question

Suppose f is a function satisfying $f(x + y) + f(x) + f(y)$ for all $x, y ∈N$ and $f(1)=\frac{1}{5}$. If $∑_{n=1}^{m} \frac{f(n)}{n(n+1)(n+2)}=\frac{1}{2}$, then m is equal to _______.

Answer 1

The correct answer is 10