In this short note the authors give answers to the three open problems formulated by Wu and Srivastava [Appl. Math. Lett. 25 (2012), 1347-1353]. We disprove the Problem 1, by showing that there exists a triangle which does not satisfies the proposed inequality. We prove the inequalities conjectured in Problems 2 and 3. Furthermore, we introduce an optimal refinement of the inequality conjectured on Problem 3.