MathematicsMedium110×since 2002Q3864Let f : R →\to→ R be a function which satisfies f(x + y) = f(x) + f(y) ∀\forall∀ x, y ∈\in∈ R. If f(1) = 2 and g(n) = ∑k=1(n−1)f(k)\sum\limits_{k = 1}^{\left( {n - 1} \right)} {f\left( k \right)}k=1∑(n−1)f(k), n ∈\in∈ N then the value of n, for which g(n) = 20, is :A20B9C5D4Check answerSkip