Interview questions
Brain teaser interview questions for investment banking
Brain teasers and market questions check how you think under pressure and whether you follow the markets. The answer matters, but so does narrating your reasoning: interviewers want to hear the steps, not a number after a long silence.
Which brain teasers and market questions should you know?
The 4 below are free in Superday Room, each with a short answer, the mistake to avoid and a target time out loud.
What's the angle between the hour and minute hands at 3:15?
7.5 degrees. At 15 minutes past, the minute hand points at 90 degrees from 12. The hour hand moves 30 degrees an hour, or 0.5 degrees a minute, so at 3:15 it sits at 90 + 7.5 = 97.5 degrees. The difference is 7.5 degrees. Say the reasoning out loud as you go.
Common mistake: Answering 0 degrees by assuming the hour hand sits exactly on the 3.
What's 15% of 360? And what's 1.08 to the 3rd power, roughly?
15% of 360 is 54: 10% is 36 and 5% is 18. 1.08³ is about 1.26: 1.08 × 1.08 = 1.1664, and 1.1664 × 1.08 ≈ 1.2597. Narrate the shortcuts so the interviewer can follow your thinking.
Common mistake: Going silent while you calculate, or rounding too early.
Pitch me a stock.
Start with the company, ticker and current price and a one-line thesis. Give two or three specific reasons with numbers: growth, margins, catalysts. Explain the valuation: why the stock is mispriced against peers or its own history. Then name the main risks and what would prove you wrong. Pick a company you can defend through ten minutes of follow-up questions.
Common mistake: Saying there are no risks, or promising a return.
Where are interest rates and the S&P 500 roughly right now, and what's been moving them?
Give approximate current levels for the federal funds target range, the 10-year Treasury yield and the S&P 500, then two or three recent drivers such as inflation data, Federal Reserve decisions, earnings and economic news. These change every day, so check them the morning of the interview at the source: the Federal Reserve for the target range and the US Treasury for yields.
Common mistake: Being far off on the levels, or not knowing what moved markets recently.
How should you talk through a brain teaser?
Out loud, step by step: restate the question, give your approach, do the math in round numbers, then sanity-check the answer.
- Repeat the question in your own words to confirm it.
- State your approach before you start: "I'll work out where each hand is, then subtract."
- Do the math out loud in round steps, like 10% then 5%.
- Give the answer, then sanity-check it in one sentence.
What brain teaser interview questions come up in finance interviews?
Mostly short logic puzzles with one clean answer: clock angles, ranking under constraints, probability, measuring time and expected value. Here are six common types with worked answers. Try each one out loud before you read the answer.
| Teaser | Answer | The idea it tests |
|---|---|---|
| 25 horses, 5 per race | 7 races | Eliminating what can't be true |
| Three ants on a triangle | 3/4 chance of a collision | Counting the outcomes |
| Two ropes, 45 minutes | Light one rope at both ends | Using what you know, not what you don't |
| 9 balls, one heavier | 2 weighings | Splitting into thirds |
| Roll a die, one reroll | Expected value $4.25 | Decision rules and expected value |
| Clock hands overlapping | 22 times a day | Relative speed |
You have 25 horses and a track that races 5 at a time, with no timer. How many races to find the 3 fastest?
Seven. Race the horses in five groups of five (5 races). Race the five group winners (race 6): the winner is the fastest horse overall. Now only five horses can still be second or third: the horses that came 2nd and 3rd in race 6, the 2nd and 3rd from the fastest horse's group, and the 2nd from the group of the horse that came 2nd in race 6. Every other horse has at least three horses known to be faster. Race those five (race 7); the top two are second and third overall.
Three ants sit on the corners of a triangle. Each picks a direction at random and walks along an edge. What's the chance none of them collide?
1/4, so the chance of a collision is 3/4. Each ant has two choices, so there are 2 × 2 × 2 = 8 equally likely outcomes. Nobody collides only if all three go the same way, clockwise or counterclockwise: 2 of the 8. That's 2/8 = 1/4. The common follow-up, with four ants on a square, works the same way: 2 of 16, or 1/8.
You have two ropes that each take exactly an hour to burn, but burn unevenly. How do you measure 45 minutes?
Light rope A at both ends and rope B at one end. Rope A burns out in 30 minutes, however uneven it is, because the two flames together cover the whole rope in half the time. At that moment rope B has 30 minutes left, so light its other end: it burns out 15 minutes later. 30 + 15 = 45 minutes. The trap is trying to cut a rope in half, which doesn't work when it burns unevenly.
You have 9 identical-looking balls. One is heavier. With a balance scale, how few weighings find it?
Two. Split the balls into three groups of three. Weigh group 1 against group 2. If one side is heavier, the heavy ball is in that group; if they balance, it's in group 3. Then take the three suspect balls and weigh one against another: the heavier side is the ball, or if they balance, it's the one you left off. Each weighing has three outcomes, so it can cut the field to a third, and 3 × 3 = 9.
I roll a die and pay you the number in dollars. After the first roll you can roll once more, but then you must take the second roll. What's the game worth?
$4.25. If you reroll, you expect (1 + 2 + 3 + 4 + 5 + 6) ÷ 6 = $3.50. So keep a first roll of 4, 5 or 6 and reroll a 1, 2 or 3. Half the time you keep, averaging (4 + 5 + 6) ÷ 3 = $5.00; half the time you reroll and expect $3.50. 0.5 × 5.00 + 0.5 × 3.50 = $4.25. The interviewer often then asks what you'd pay to play: anything below $4.25 has a positive expected value.
How many times a day do the hour and minute hands of a clock overlap?
22 times. The minute hand gains on the hour hand at 360 – 30 = 330 degrees an hour, so it laps the hour hand every 360 ÷ 330 = 12/11 hours, about every 65.45 minutes. In 12 hours that's 12 ÷ (12/11) = 11 overlaps, not 12, because the hands meet at 12:00 and don't meet again until about 1:05. Twice that is 22 a day.
If you get stuck, say so and keep reasoning out loud: “I'd start by ruling out horses that can't be in the top three.” Interviewers usually care more about a clear method than a fast number, and many will give a hint if you're heading the right way.
Which firms ask these questions?
In Superday Room's bank, candidates reported 254 brain teasers and market questions from interviews at 28 named firms. The firms with the most reports: J.P. Morgan (25), Centerview Partners (23), Goldman Sachs (21), Moelis & Co. (21), Morgan Stanley (21) and Evercore (18). These are candidates' reports, counted November 1, 2026. Questions by firm →
Superday Room's full bank has more than 290 brain teasers and market questions. The 4 on this page are free to practice out loud; the rest come with the Recruiting Season Pass.