Yes, solving previous years' papers of UPSC Chemistry optional can help in improving problem-solving speed. Here's how:

1. Familiarity with exam pattern and question types:
- Solving previous years' papers gives you an idea about the exam pattern, structure, and the types of questions that are asked in the UPSC Chemistry optional exam.
- It helps you understand the distribution of marks and the weightage given to different topics, which can guide your preparation strategy.

2. Practice and revision:
- By solving previous years' papers, you get to practice a wide range of questions from different topics in chemistry.
- It helps in revising and reinforcing your understanding of the subject.
- Regular practice also helps in improving your speed and accuracy in solving problems.

3. Exposure to different question formats:
- UPSC Chemistry optional exam may include various types of questions, such as multiple-choice questions, numerical problems, conceptual questions, and analytical reasoning questions.
- Solving previous years' papers exposes you to the different formats of questions, helping you understand how to approach and solve them efficiently.

4. Time management:
- Solving previous years' papers under timed conditions helps in improving your time management skills.
- It allows you to evaluate how much time you should allocate to each question or section, ensuring that you complete the paper within the given time frame.

5. Identifying weak areas:
- Solving previous years' papers helps in identifying your weak areas or topics where you need more practice.
- It allows you to analyze your performance, identify patterns of mistakes, and focus on improving those areas.

6. Building confidence:
- Regularly solving previous years' papers helps in building confidence by familiarizing you with the exam format and increasing your comfort level with the subject.
- It boosts your self-assurance and reduces exam anxiety, leading to better performance on the actual exam day.

Conclusion:
Solving previous years' papers of UPSC Chemistry optional is an effective strategy to improve problem-solving speed. It helps in familiarizing yourself with the exam pattern, practicing a wide range of questions, managing time efficiently, identifying weak areas, and building confidence. Regular practice and revision using previous years' papers will enhance your overall preparation and increase your chances of success in the UPSC Chemistry optional exam.