## Introduction to Equity Research Brain Teaser Interview Questions

Equity research brain teaser interview questions are a common component of interviews for positions in the field of equity research. These questions are designed to test a candidate's analytical thinking, problem-solving skills, and ability to think quickly under pressure. Brain teasers often involve complex financial scenarios or mathematical puzzles that require candidates to demonstrate their knowledge of financial concepts and their ability to apply them in real-world situations. In this competitive field, being able to effectively navigate and answer brain teaser questions can set candidates apart and showcase their readiness for the challenges of equity research roles.

### 25 Brain Teaser Equity Research Interview Questions and Answers

**How many times can you subtract 10 from 100?**

**Suggested Answer:**

The answer to this brain teaser is quite straightforward but often misinterpreted. You can subtract 10 from 100 **only once** if you consider the phrasing literally. After you subtract 10 the first time, you are no longer subtracting from 100; instead, you are subtracting from 90.Thus, the correct interpretation is:

You can subtract 10 from 100

**one time**before you are no longer working with 100.

If you were to continue subtracting 10 from the resulting numbers (90, 80, etc.), you could do that multiple times, but the question specifically asks about subtracting from 100.

**If you have two coins that add up to 30 cents and one of them is not a nickel, what are the two coins?**

**Suggested Answer:**

The solution to this brain teaser involves a bit of lateral thinking. The two coins that add up to 30 cents are:

**One quarter (25 cents)****One nickel (5 cents)**

The key to the riddle is in the phrasing: "one of them is not a nickel." This statement is true because the quarter is not a nickel. However, the other coin can indeed be a nickel. Thus, the two coins are a quarter and a nickel, totaling 30 cents.

**You have a 3-gallon jug and a 5-gallon jug. How do you measure out exactly 4 gallons of water using only these two jugs?**

**Suggested Answer:**

To measure exactly 4 gallons of water using a 3-gallon jug and a 5-gallon jug, follow these steps:

**Fill the 5-gallon jug completely.**

Now you have 5 gallons in the 5-gallon jug and 0 gallons in the 3-gallon jug.

**Pour water from the 5-gallon jug into the 3-gallon jug until the 3-gallon jug is full.**

You pour 3 gallons into the 3-gallon jug, leaving you with 2 gallons in the 5-gallon jug.

Status: 5-gallon jug = 2 gallons, 3-gallon jug = 3 gallons.

**Empty the 3-gallon jug.**

Now you have 2 gallons in the 5-gallon jug and 0 gallons in the 3-gallon jug.

Status: 5-gallon jug = 2 gallons, 3-gallon jug = 0 gallons.

**Pour the remaining 2 gallons from the 5-gallon jug into the 3-gallon jug.**

Now the 3-gallon jug has 2 gallons, and the 5-gallon jug is empty.

Status: 5-gallon jug = 0 gallons, 3-gallon jug = 2 gallons.

**Fill the 5-gallon jug completely again.**

You now have 5 gallons in the 5-gallon jug and 2 gallons in the 3-gallon jug.

**Pour from the 5-gallon jug into the 3-gallon jug until the 3-gallon jug is full.**

Since the 3-gallon jug already has 2 gallons, it can only take 1 more gallon from the 5-gallon jug.

After this step, you will have exactly 4 gallons left in the 5-gallon jug.

Status: 5-gallon jug = 4 gallons, 3-gallon jug = 3 gallons.

**Conclusion**

By following these steps, you successfully measure out exactly **4 gallons** of water using the 3-gallon and 5-gallon jugs!

**A man pushes his car to a hotel and tells the owner he’s bankrupt. Why?**

**Suggested Answer:**

This brain teaser is a classic riddle that plays on the context of the situation. The answer is:The man is playing a game of Monopoly.

**Explanation:**

In Monopoly, players move around the board by pushing their game pieces (which can be represented as cars) and can land on properties, including hotels.

If a player lands on a hotel owned by another player and cannot afford to pay the rent, they may declare bankruptcy.

Thus, the man pushes his car (game piece) to a hotel and tells the owner he’s bankrupt because he cannot pay the rent in the game. This riddle highlights the importance of context and the different meanings words can have in various scenarios.

**There are three light switches outside a room, each of which controls one of three light bulbs inside the room. You can only enter the room once. How do you determine which switch controls which bulb?**

**Suggested Answer:**

To figure out which of the three light switches controls each of the three light bulbs inside the room, follow these steps:

**Turn on the first switch (Switch A)**and leave it on for about 5-10 minutes.**After the time has passed, turn off Switch A**and then turn on the second switch (Switch B).**Now, enter the room**where the light bulbs are located.**Observe the bulbs:**

The bulb that is

**on**corresponds to**Switch B**(the one you just turned on).The bulb that is

**off but warm**corresponds to**Switch A**(the one you turned on earlier and then off).The bulb that is

**off and cold**corresponds to**Switch C**(the switch that was never turned on).

By using this method, you can accurately determine which switch controls which bulb with only one entry into the room.

**You have a 9-minute hourglass and a 4-minute hourglass. How do you measure exactly 7 minutes?**

**Suggested Answer:**

To measure exactly 7 minutes using a 9-minute hourglass and a 4-minute hourglass, follow these steps:

**Start both hourglasses at the same time.**

At this point, the 9-minute hourglass is counting down from 9 minutes, and the 4-minute hourglass is counting down from 4 minutes.

**When the 4-minute hourglass runs out (after 4 minutes):**

Immediately flip the 4-minute hourglass to start it again.

At this point, 4 minutes have passed, and there are 5 minutes left in the 9-minute hourglass.

**When the 4-minute hourglass runs out again (after another 4 minutes):**

This will be at the 8-minute mark (4 minutes from the first run and 4 minutes from the second run).

At this time, the 9-minute hourglass has 1 minute left (since it started with 9 minutes and 8 minutes have passed).

**Now, immediately flip the 4-minute hourglass again.**

The 9-minute hourglass will run out after 1 more minute, which will bring the total time to 9 minutes.

**When the 9-minute hourglass runs out (after 1 minute):**

At this point, you have measured a total of 9 minutes. However, you need to measure 7 minutes, so you can stop here.

**Summary of Timing:**

The first 4 minutes (4-minute hourglass runs out).

The next 4 minutes (4-minute hourglass runs out again).

The final 1 minute (9-minute hourglass runs out).

By following this sequence, you can measure exactly **7 minutes** using the two hourglasses!

**If you have a 5-quart jug and a 3-quart jug, how can you measure exactly 1 quart of water?**

**Suggested Answer:**

To measure exactly 1 quart of water using a 5-quart jug and a 3-quart jug, follow these steps:

**Fill the 5-quart jug completely.**

**Pour water from the 5-quart jug into the 3-quart jug until it is full.**

This leaves 2 quarts in the 5-quart jug (5 - 3 = 2).

**Empty the 3-quart jug.**

**Pour the remaining 2 quarts from the 5-quart jug into the 3-quart jug.**

This leaves 1 quart in the 5-quart jug (2 - 3 = -1, but since the jug cannot hold negative amounts, it is 1 quart).

**Fill the 5-quart jug completely.**

**Pour water from the 5-quart jug into the 3-quart jug until it is full.**

This leaves 4 quarts in the 5-quart jug (5 - 3 = 2).

At this point, you have 1 quart in the 5-quart jug, which is the desired amount.By following these steps, you can measure exactly **1 quart** of water using the 5-quart and 3-quart jugs.

**A rooster lays an egg on the peak of a barn roof. Which way does it roll?**

**Suggested Answer:**

The answer to this riddle is that **a rooster does not lay eggs**.

**Explanation:**

Roosters are male chickens and do not have the biological capability to lay eggs. Therefore, the scenario presented is impossible, and there is no egg to roll in any direction.

**What has cities, but no houses; forests, but no trees; and rivers, but no water?**

**Suggested Answer:**

The answer to this riddle is **a map**.

**Explanation:**

A map represents cities, but it does not contain actual houses.

It can depict forests, but there are no real trees on a map.

It shows rivers, but there is no water present.

**How can you throw a ball as hard as you can and have it come back to you, even if it doesn’t hit anything?**

**Suggested Answer:**

To have a ball come back to you after throwing it as hard as you can without hitting anything, you need to throw the ball **straight up in the air**.

**Explanation:**

When you throw the ball straight up, gravity will pull it back down.

The ball will reach a point where its upward momentum is completely spent, and it will begin to fall back down.

As it falls, gravity accelerates the ball downward, and it will return to your position.

As long as you throw the ball straight up and catch it when it comes back down, you can have it return to you without hitting anything else. This works because of the Earth's gravity and the ball's trajectory when thrown vertically upward.

**What can travel around the world while staying in a corner?**

**Suggested Answer:**

The answer to this riddle is **a stamp**.

**Explanation:**

A stamp is placed in the corner of an envelope.

When the envelope is mailed, it can travel around the world while the stamp itself remains in the corner of the envelope.

This riddle cleverly plays on the concept of travel and positioning, highlighting how something small and seemingly insignificant can be part of a much larger journey.

**What gets wetter the more it dries?**

**Suggested Answer:**

The answer to this riddle is **a towel**.

**Explanation:**

A towel is used to dry things, such as your body or hands.

As it absorbs moisture from these surfaces, the towel itself becomes wetter.

This riddle plays on the paradox of drying and wetness, creating a clever twist that highlights the towel's function. It’s a great example of how language can be used to create unexpected meanings!

**What has keys but can’t open locks?**

**Suggested Answer:**

The answer to this riddle is **a piano**.

**Explanation:**

A piano has keys, which are the individual levers that produce musical notes when pressed.

However, these keys cannot open locks, as they serve a completely different function related to music.

This riddle cleverly plays on the dual meaning of the word "keys," leading to an unexpected yet logical answer. It highlights the importance of context in understanding language and meaning!

**A man is looking at a photograph of someone. His friend asks who it is. The man replies, “Brothers and sisters, I have none. But that man’s father is my father’s son.” Who is in the photograph?**

**Suggested Answer:**

The man says, “Brothers and sisters, I have none. But that man’s father is my father’s son.”

**"My father's son"**refers to the man himself, since he has no brothers or sisters.Therefore,

**"that man's father"**is the man himself.

This means that the person in the photograph is his **son**.

**Conclusion:**

The man in the photograph is the **son** of the man who is looking at the photograph.

**How many seconds are there in a year?**

**Suggested Answer:**

That's an interesting question. To provide an accurate answer, we need to define the specific year we're considering. A leap year, for instance, has 366 days, while a common year has 365.

Assuming we're talking about a common year with 365 days:

There are 60 seconds in a minute.

There are 60 minutes in an hour.

There are 24 hours in a day.

Therefore, there are 60 * 60 * 24 = 86,400 seconds in a day.

For a common year, with 365 days, the total number of seconds would be 86,400 seconds/day * 365 days = 31,536,000 seconds.

**If you have a bowl with six apples and you take away four, how many do you have?**

**Suggested Answer:**

If I have a bowl with six apples and I take away four, I would have **two apples** remaining in my hands.

**What has a head, a tail, is brown, and has no legs?**

**Suggested Answer:**

This brain teaser is asking about an object that has a head and a tail, is brown in color, and has no legs. Let's think through the possibilities:

**Analyzing the Clues**

**Has a head and a tail:**

This suggests a coin or a coin-like object.

**Is brown in color:**

Most coins are made of metals that have a brownish hue, such as copper or brass.

**Has no legs:**

Coins do not have legs.

**Conclusion**

Based on the given clues, the most likely answer is:

**A penny or a coin.**A penny or any coin in general fits all the criteria mentioned in the brain teaser. It has a head (the image of a person) and a tail (the image of a building or a symbol), is typically brown in color due to its copper or brass composition, and, of course, has no legs.

**How do you make the number 7 even without addition, subtraction, multiplication, or division?**

**Suggested Answer:**To make the number 7 even without using any mathematical operations, we can simply change its linguistic form. By adding 'n' to it, we get 'seven', which is a word, not a number. Therefore, it doesn't fit the criteria of being odd or even.

**There are three boxes, one containing only apples, one containing only oranges, and one containing both apples and oranges. Each box is labeled incorrectly. You may pick one fruit from one box without looking inside. How can you correctly label all the boxes?**

**Suggested Answer:**This classic logic puzzle requires careful reasoning to solve the labeling issue with the boxes. Let’s break it down step by step.

**Problem Setup**

**Three Boxes:**

Box A: Labeled "Apples"

Box B: Labeled "Oranges"

Box C: Labeled "Apples and Oranges"

**Key Information:**

Each box is labeled incorrectly.

**Solution Steps**

**Step 1: Choose a Fruit**

Since all boxes are labeled incorrectly, we can start by picking a fruit from the box labeled "Apples and Oranges." This box cannot contain both types of fruit, so it must contain only one type.

**Step 2: Analyze the Outcome**

**If you pick an apple**from the "Apples and Oranges" box:This box must actually contain only

**apples**.Therefore, the box labeled "Oranges" (which is also incorrectly labeled) cannot contain only oranges; it must contain both apples and oranges.

Consequently, the box labeled "Apples" must contain only

**oranges**.**If you pick an orange**from the "Apples and Oranges" box:This box must actually contain only

**oranges**.Therefore, the box labeled "Apples" (which is incorrectly labeled) cannot contain only apples; it must contain both apples and oranges.

Consequently, the box labeled "Oranges" must contain only

**apples**.

**Step 3: Relabel the Boxes**

Based on the fruit picked, you can now correctly label all the boxes:

If you picked an apple:

Box labeled "Apples and Oranges" →

**Apples**Box labeled "Oranges" →

**Apples and Oranges**Box labeled "Apples" →

**Oranges**If you picked an orange:

Box labeled "Apples and Oranges" →

**Oranges**Box labeled "Apples" →

**Apples and Oranges**Box labeled "Oranges" →

**Apples**

**Conclusion**

By picking just one fruit from the box labeled "Apples and Oranges," you can deduce the correct contents of all three boxes.

**You are given 12 identical-looking balls, one of which is either heavier or lighter. How can you determine the odd ball using a balance scale in just three weighings?**

**Suggested Answer:**

This is a classic problem in logic and deduction that can be solved through a systematic approach. Here’s how to determine the odd ball among the 12 identical-looking balls using a balance scale in just three weighings.

**Step-by-Step Solution**

**Step 1: Divide the Balls**

**Divide the 12 balls into three groups of four:**

Group A: Balls 1, 2, 3, 4

Group B: Balls 5, 6, 7, 8

Group C: Balls 9, 10, 11, 12

**Step 2: First Weighing**

**Weigh Group A against Group B:**

**Case 1:**If they balance, then the odd ball is in Group C (balls 9, 10, 11, 12).**Case 2:**If they do not balance, you will know which group contains the odd ball and whether it is heavier or lighter.

**Step 3: Second Weighing**

**If Case 1 (A = B):**

**Weigh three balls from Group C against three balls from either Group A or B (which are known to be normal):**

For example, weigh balls 9, 10, and 11 from Group C against balls 1, 2, and 3 from Group A.

**If they balance:**The odd ball is ball 12.**If they do not balance:**You will determine if one of balls 9, 10, or 11 is the odd ball and whether it is heavier or lighter.

**If Case 2 (A ≠ B):**

**Assume Group A is heavier (A > B) and take three balls from Group A and three from Group B:**

Weigh balls 1, 2, and 5 against balls 3, 4, and 6.

**If they balance:**The odd ball is one of balls 7 or 8, and you know whether it is heavier or lighter based on the first weighing.**If they do not balance:**You will determine which specific balls are the odd ones and whether they are heavier or lighter.

**Step 4: Third Weighing**

**If you have narrowed it down to three balls:**

**Weigh two of the suspected balls against each other:**

If one is heavier or lighter, you have identified the odd ball.

If they balance, the third ball is the odd one.

**Conclusion**

By following this systematic approach, you can identify the odd ball among the 12 in just three weighings.

**What comes once in a minute, twice in a moment, but never in a thousand years?**

**Suggested Answer:**

This brain teaser is a clever play on words and requires lateral thinking. Let’s analyze the question:

**The Riddle**

The question states: **"What comes once in a minute, twice in a moment, but never in a thousand years?"**

**Analyzing the Clues**

**Once in a minute:**

This suggests that whatever we are looking for appears one time in the word "minute."

**Twice in a moment:**

This indicates that the same thing appears two times in the word "moment."

**Never in a thousand years:**

This means that it does not appear at all in the phrase "a thousand years."

**Conclusion**

The answer to the riddle is:**The letter "m."**

It appears

**once**in the word "minute."It appears

**twice**in the word "moment."It does not appear at all in the phrase "a thousand years."

This riddle emphasizes the importance of careful observation and thinking outside the box, skills that are essential in equity research for analyzing data and identifying trends that may not be immediately obvious.

**If you’re in a dark room with a candle, a wood stove, and a gas lamp, and you only have one match, what do you light first?**

**Suggested Answer:**

This brain teaser is designed to test your ability to think critically and pay attention to the details of the scenario. Let’s analyze the situation:

**The Scenario**

You are in a dark room with the following items:

A candle

A wood stove

A gas lamp

One match

**The Key Question**

The question asks: **"What do you light first?"**

**Conclusion**

The answer is:**You light the match first.**

**Explanation**

Before you can light any of the other items (the candle, the wood stove, or the gas lamp), you need to light the match. This riddle emphasizes the importance of understanding the sequence of actions and highlights the need for logical reasoning in problem-solving.

**You see a boat filled with people, yet there isn’t a single person on board. How is that possible?**

**Suggested Answer:**

This brain teaser plays with the interpretation of the words used in the scenario. Let’s analyze the statement:

**The Scenario**

The question states: **"You see a boat filled with people, yet there isn’t a single person on board."**

**Key Insight**

The phrase "not a single person" can be interpreted literally.

**Conclusion**

The answer is:**All the people on the boat are married.**

**Explanation**

The riddle cleverly uses the word "single" to imply that there are no unmarried (or single) individuals on the boat. Therefore, while the boat is filled with people, there are no "single" people aboard.This type of lateral thinking is essential in equity research, as it encourages one to look beyond the obvious and consider different perspectives, which can lead to more comprehensive analyses and insights in financial evaluations.

**What has many keys but can’t open a single lock?**

**Suggested Answer:**

This brain teaser is another clever play on words that requires lateral thinking. Let’s analyze the question:

**The Riddle**

The question states: **"What has many keys but can’t open a single lock?"**

**Analyzing the Clue**

**"Many keys":**This suggests that the answer involves something that has multiple keys.**"Can’t open a single lock":**This indicates that, despite having keys, it cannot perform the function of unlocking.

**Conclusion**

The answer is:**A piano.**

**Explanation**

A piano has many keys (typically 88 on a standard piano), but none of these keys can open a lock.

**What is as light as a feather, yet the strongest man cannot hold it for more than 5 minutes?**

**Suggested Answer:**

This brain teaser presents an intriguing paradox. Let's analyze the clues:

**The Riddle**

The question states: **"What is as light as a feather, yet the strongest man cannot hold it for more than 5 minutes?"**

**Analyzing the Clues**

**"As light as a feather":**This suggests that the object is extremely lightweight.**"The strongest man cannot hold it for more than 5 minutes":**This implies that the object has a significant impact on the person holding it, despite its lightweight nature.

**Conclusion**

The answer is:**Your breath.**

**Explanation**

Your breath is as light as a feather, but the act of holding your breath can be challenging, even for the strongest person. After a certain period (typically less than 5 minutes), the body's need for oxygen becomes overwhelming, and the person must breathe.

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