Introduction  

Investment banking interviews can be some of the most intense and challenging job screenings you'll ever face. In addition to questions about your experience, technical know-how, and understanding of the industry, you'll likely encounter a set of brain teasers. These questions are designed to evaluate your analytical and problem-solving abilities in a high-stakes, time-sensitive environment. In this article, we'll explore why brain teasers are often used in investment banking interviews, delve into the types of questions you might encounter, and provide examples with answers. 

The Role of Brain Teasers: Why Are They Used? 

Testing Problem-Solving Skills 

Investment banking involves complex financial models, intricate transactions, and solving challenging issues that can come up in the eleventh hour. Brain teasers can quickly assess your ability to solve problems efficiently. 

Gauging Under Pressure Performance 

In a fast-paced environment like investment banking, working under pressure isn't just an occasional requirement; it's an everyday affair. Brain teasers test your ability to think quickly and clearly when the heat is on. 

Assessing Analytical Abilities 

Being able to dissect a problem, analyse its components, and find a logical solution is essential in the world of high-stakes finance. Brain teasers in interviews are a quick and effective way to measure these skills. 

Popular Types of Brain Teasers 

Mathematical Puzzles 

These usually involve straightforward calculations but may come with a tricky twist. You're generally not allowed to use a calculator, so your mental arithmetic skills are put to the test. 

Logical Reasoning Questions 

Here, you'll be presented with a scenario, often abstract, and asked to deduce the outcome using logical reasoning. 

Word Problems 

These are often based on real-world business scenarios and require both math and analytical skills to solve. 

Examples of Brain Teasers with Answers 

Example 1 

Question: You have a 3-gallon jug and a 5-gallon jug. How can you measure out exactly 4 gallons? 
Answer: Fill the 5-gallon jug and pour it into the 3-gallon jug until full. Empty the 3-gallon jug and pour the remaining 2 gallons from the 5-gallon jug into the 3-gallon jug. Refill the 5-gallon jug and add to the 3-gallon jug until it's full. You're left with 4 gallons in the 5-gallon jug. 

Example 2 

Question: A bat and a ball together cost $1.10. The bat costs $1 more than the ball. How much does the ball cost? 
Answer: The ball costs 5 cents, and the bat costs $1.05. 

Example 3 

Question: How many golf balls can fit in a school bus? 
Answer: There's no right answer; the question assesses how you approach problems of scale and estimation. 

How to Prepare for Brain Teasers 

Familiarise Yourself 

Research the types of questions that commonly appear in investment banking interviews to familiarise yourself with the format and style. 

Practice, Practice, Practice 

The more you practice, the better you'll become at quickly identifying the type of problem and employing the correct strategy to solve it. 

Conclusion 

Brain teasers can seem intimidating, but remember: they are tools interviewers use to gauge your problem-solving and analytical abilities. Preparation is key. By understanding why these questions are asked and how best to approach them, you'll not only improve your chances of acing the interview but also gain valuable skills that will serve you well in your investment banking career.