This paper identifies limitations of traditional reinforcement learning (RL) in enhancing the multi-level inference capability of large-scale language inference models (LLMs) and proposes Question Augmentation (QuestA), a novel approach to address these limitations. QuestA is a simple yet effective strategy that provides partial solutions during RL training, reducing the difficulty of the problem and providing more informative training signals. Applying QuestA during RL training for mathematical inference tasks improves Pass@1 and Pass@k performance, particularly on problems where traditional RL struggles. Applying QuestA to powerful open-source models such as DeepScaleR and OpenMath Nemotron, we achieve state-of-the-art results (67.1%, 59.5%, and 35.5%, respectively) on the AIME24, AIME25, and HMMT25 benchmarks. Furthermore, we provide a theoretical explanation for QuestA's improved sample efficiency, suggesting a practical and generalizable approach for extending inference capability using RL.