Problem
ALG-B1-M12-P008 Variant 2, Problem 4
#8
★★☆☆☆ Level 2 of 5
\(f:\mathbb Q\to\mathbb Q\), \(f(x+y)=f(x)+f(y)\), \(f(2)=6\). Find \(f\left(\frac{5}{3}\right)\).
Find \(f(1)\).
\(f(1)=3\), so \(f(q)=3q\). Answer: \(5\).
Mock olympiad problem. Tags: cauchy-equation.