# IBM Interview Questions with Answers

8 previously-asked interview questions from IBM's hiring process, each with the correct answer and a worked explanation. Written against the company's actual test pattern.

_Source: Astra (https://useastra.in). Updated 2026-09-05._

### 1. What is cloud computing?

**Answer:** Cloud computing delivers computing resources such as servers, storage, databases, and software over the internet on demand, typically pay as you go. Models include IaaS, PaaS, and SaaS, offering scalability, flexibility, and reduced upfront cost.

**Explanation:** On-demand computing resources over the internet.

### 2. When would you use SQL versus Python for a data task?

**Answer:** Use SQL to query, filter, join, and aggregate data directly in a database efficiently. Use Python for complex transformations, statistical analysis, machine learning, automation, and visualisation. They are complementary and often used together.

**Explanation:** SQL for in-database querying; Python for analysis and ML.

### 3. What is machine learning?

**Answer:** Machine learning is a branch of AI where systems learn patterns from data to make predictions or decisions without being explicitly programmed for each case. It includes supervised, unsupervised, and reinforcement learning.

**Explanation:** Systems that learn patterns from data to predict or decide.

### 4. What is the difference between a list and an array?

**Answer:** An array stores elements of the same type in contiguous memory with fixed size and O(1) index access. A list (for example a Python list or a linked list) can be dynamic in size and, depending on the type, may allow mixed types or cheaper insertions at the cost of access speed.

**Explanation:** Array: fixed, contiguous, same type. List: dynamic, flexible.

### 5. What is the difference between supervised and unsupervised learning?

**Answer:** Supervised learning trains on labelled data to predict outputs (classification, regression). Unsupervised learning finds structure in unlabelled data (clustering, dimensionality reduction). The key difference is whether labels are available during training.

**Explanation:** Supervised uses labels; unsupervised finds structure without labels.

### 6. What is version control and why is it important?

**Answer:** Version control tracks changes to code over time, enabling collaboration, history, branching, and rollback. Git is the most common system. It prevents lost work, supports parallel development, and records who changed what and why.

**Explanation:** Tracks code changes for collaboration, history, and rollback.

### 7. Tell me about yourself.

**Answer:** Give a concise 60 to 90 second overview: your degree, key technical skills, a project or internship with its impact, and why IBM interests you. Keep it structured and relevant.

**Explanation:** Structured pitch: background, skills, project, fit.

### 8. Why do you want to join IBM?

**Answer:** Mention IBM legacy and leadership in enterprise technology, cloud, AI (watsonx), and consulting, its strong learning culture and global exposure, and the chance to work on impactful enterprise solutions. Tie it to your interests.

**Explanation:** Enterprise tech, cloud and AI, learning culture.

More IBM preparation, including the full recruitment process: https://useastra.in/campus/ibm