Top 14 Guesstimate Questions And Answers For Interview

Guesstimate questions are important from management interview point of view. These questions are critical for assessing candidate’s take on a problem that lacks complete information.

Guesstimate is the portmanteau of guess and estimate. “How many soaps are sold daily in India?”, “How many cups of coffee are being consumed daily in Delhi?”. These are some of the guesstimate questions. These can only be solved approximately based on the available information.

Table of Contents

• What is Guesstimate?
• Importance of Guesstimate questions
• Types of Guesstimate Questions Asked in Interviews
• Interview-Based Guesstimate Questions with Answers
• Tips to answer Guesstimate Interview Questions

What is Guesstimate?

Guesstimate is an approximation based on the available information. Most of the time, only limited information is available. It has more to do with understanding the approach toward the problem. Consider feasible parameters that influence the problem. Interviewers ask such questions to understand if the candidate can come up with a solution to a problem within a set time frame.

Importance of Guesstimate Interview Questions

Guesstimate questions are prepared on the basis of limited details and information. These questions compel the interviewee to use their reasoning and problem-solving abilities. Such questions are valuable in several fields where you may have to make decisions based on the availability of a few resources. Through these questions, one can gain a different perspective on how a problem can be solved. Guesstimate interview questions are often asked in MBA interviews.

Types of Guesstimate Questions Asked in Interviews

Guesstimate questions can be of different formats. The aim of these questions is to assess whether the candidate has the capability to handle unfamiliar scenarios. The following types of guesstimate interview questions are common.

1. Population Estimation Guesstimates

Population-based guesstimate questions require candidates to estimate the number of people within a specific area. The aim of these guesstimates for interview is to assess the candidate’s capability to segment populations based on the information available.

How To Answer Guesstimate Questions Related to Population Estimation?

While answering these guesstimate questions, the candidate needs to first start with the total population of the country.  Afterwards, segmentation of demographics will be needed. 

The following questions are guesstimate examples to be considered before going to the interview:

• How many people buy smartphones in India annually?
• How many people purchase milk daily in urban areas?
• How many people watch Netflix in India monthly?
• How many people use online food delivery services monthly?
• How many people use metro services in major metropolitan areas?

2. Market Sizing Guesstimates Questions

These types of guesstimate interview questions are meant to assess the size or potential value of a market. These guesstimate questions for interviews are common when it comes to consulting and marketing roles. Through these questions, the interviewer tries to determine whether the professional is capable of understanding the size of the target market before making strategic decisions.

How To Answer Guesstimate Questions Related to Market Sizing?

To answer this type of guesstimate interview questions, candidates need to first break down the population into relevant segments. They further need to consider factors that can influence the market sizing such as consumer habits, market penetration and consumption habits.

Here are some Guesstimate examples:

• How many refrigerators are sold annually in India?
• What is the total market size for contact lenses in the US?
• How many pizzas are ordered in New York City on a daily basis?
• What is the potential market for smartphone screen protectors in Europe?
• How many pairs of running shoes are sold every year globally?

3. Resource Allocation Guesstimate Interview Questions

Resource allocation guesstimate interview questions require candidates to estimate the resources required for an event or project including seats, materials, or facilities. These guesstimate questions for interview are asked by interviewers for operations and event management roles. The aim is to assess the planning skills of the candidate.

How To Answer Guesstimate Questions Related to Resource Allocation?

For these guesstimate questions, candidates need to first start with the number of participants. Based on the number of candidates, resource requirements for each person need to be calculated. Any other additional factors must be included with this.

The following Guesstimate examples are relevant to the resource allocation category:

• How many textbooks should be allocated to rural schools in India?
• How many hospital beds are required in a tier-2 city?
• How much drinking water should be allocated to a village?
• How many ambulances are needed in a metropolitan area?
• How many internet towers are required in a rural district?

Top Interview-Based Guesstimate Questions and Answers

Management students are asked such questions by interviewers to analyze their decision-making and estimation capabilities. Candidates are expected to approximate the answer based on the little information that they are provided with.

Basically, your approach to answering the question is assessed. There is no actual calculation involved. Aspirants who plan to pursue a career as a consultant should also be aware of the concept. You can find below a list of interview-based guesstimate questions with solutions that can be useful to you.

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Q1. What is your strategy for solving a guesstimate question?

Ans. The four-step strategy as given below is quite useful for answering guesstimate interview questions:

Step 1: Clarify unclear terms asked in the question.
Step 2: Break down numbers into small and easy-to-estimate pieces.
Step 3: Estimate each piece mathematically and by using background knowledge.
Step 4: Consolidate every piece to conclude the result.

Q2. What are the different types of Guesstimates based on an approach to solutions?

Ans. Following are the different types of Guesstimates based on the approach to solutions:

• Household Approach: This approach is used for solving household-based guesstimate questions.
• Population Approach: For solving population-related questions guesstimate questions such as finding the number of people consuming something or the number of people living in an area.
• Structural Approach: This approach is used for solving guesstimate questions such as finding the number of aeroplanes landing in a single day.

Q3. Can you provide examples of guesstimate questions?

Ans. Some examples of these questions would be:

• How many packs of Mama Earth face packs are sold each day in India?
• Number of iPhones users in India at present
• The average number of bikes sold in Delhi during the last month
• How many teacups were consumed in Bangalore last week?

Q4. How many iPhones users are there in India at present?

Ans. Suppose, we are considering all models of the iPhone.

1. There are 1.39 billion Indians. Out of which, 40% of the population includes children and senior citizens. This means that children and senior citizens will be excluded which leaves us with 834 million people that can own an iPhone.
2. Now, out of all these people, we will consider the upper class and upper-middle class who can own an iPhone. For this, we will exclude the lower middle class, which is around 14%.
3. This brings the probable number to 717 million. As per the statistics, the market share of the iPhone is 3.2%. This means there can be 22 million possible iPhone users in India.

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Q5. How many refrigerators are sold in India every year?

Ans. First of all, clarify whether we will consider domestically produced refrigerators or both domestically and internationally manufactured refrigerators.

1. Suppose we are considering both, then we will exclude segments based on a few factors.
2. Consider the population of India and now, divide it by the average number of members in Indian Households i.e. 4 members per household.
3. Now, further segment the population into urban (tier 1), suburban (tier 2) and rural (tier 3).
4. Classify these tiers as per availability of electricity (1.3 million Indians do not have access to electricity).
5. Exclude the number of people below the poverty line.
6. Your approximation should also include the annual demand for new refrigerators and replacements.
7. Consider the average life of a refrigerator (10 years) and the annual projected growth rate of refrigerators in your calculation.

Q6. What is the average number of laptops sold in Mumbai every day?

Ans. Here, we will consider both the demand and supply of laptops. I assume that supply is more than demand since the location is Mumbai.

1. The ‘18-45’ age group will be the target market for the suppliers which is around 70% of the population of Mumbai.
2. The average cost of a laptop is around 40,000 rupees and assuming that any person who earns more than this amount can buy a laptop.
3. This comprises about 70% of the population of Mumbai.
4. Assuming that 70% of this population already owns a laptop and only 30% might purchase a new one.
5. Let us now assume that the demand for personal computers will increase by 20% whereas the demand for buying laptops will increase by 80%.
6. So, the average number of laptops= total of the above-mentioned metrics divided by the number of days in a year.

Learn to solve guesstimates and puzzles in a job interview 

Q7. What number of tennis balls can fit inside a room?

Ans. First of all, you need to know the size of the tennis ball. You can do one of the two things: ask the interviewer or assume its size.

1. Now, calculate the volume of the room and divide this volume by the volume of tennis balls. You need to consider that the balls are round and a regular arrangement will leave empty space due to their shape.
2. Suppose, the room has only 4 seats. The room may fit 5 chairs in the vertical direction and 10 chairs in the horizontal direction. It seems as if this arrangement can be repeated 10 times to fill the room. This means that the room can roughly fill 500 seats.
3. The total space occupied by the seat should be considered here (sp). Here sp= (4 x 2 x 1)ft = 8 ft. This means that the room’s volume is approximately sp x number of seats = 8 x 500 = 4000 cubic ft.
4. The tennis ball seems to occupy 4 cubic inches of area, the number of balls = volume of room/ area occupied by balls = 1000 balls.
5. Since tennis balls can be packed up to 70%, hence the total number of balls is 700.

Q8. How many balls should you take out of a bag that has red and green balls in order to get two matching balls?

Ans. Suppose that you take out a red ball and then a green ball. After two times, you will automatically get either a red or green ball which means you will own a pair of matching balls the third time.

Q9. How many cups of tea were consumed in Delhi in a month?

Ans. We will assume that fewer people will consume tea during the weekend since these are not working days. The next number to consider is the population.

There are 20 million people in the city and let us assume that 20% of youngsters do not consume tea. Out of the rest, 30% consume tea on a daily basis, 20% consume tea occasionally and 10% do not consume tea. Let us say that daily drinkers could be having three cups of tea in a day and occasional drinkers consume tea twice a week.

Then, the total number of cups of tea consumed will be:

• Daily drinkers – 3 x 0.2 x 7 = 4.2
• Occasional drinkers – 1 x 0.2 x 1 = 0.2
• Non-drinkers= 0
• Total= Daily + Occasionally + Non-drinkers = 4.4 cups in a day
• Per month = 4 x 4.4 x 1.4 crore = 24.64 crore cups.

Q10. What is the weight of the Ashoka Hotel?

Ans. This is one of the guesstimate examples that the interviewer will ask to test what factors to consider. While approximating such a question, you would also include the dimensions of the hotel, then you will include the weight of the material used for building the hotel. Whether there are people in the building or not, will also be important for the final approximation of the hotel’s weight.

Q11. How many people live in your housing society?

Ans.  Suppose that society has only apartment-style of flats. Recall the number of apartments is numbered from 1 to 40 which means that there are 40 apartments. Each apartment block has 9 floors with 3 apartments. So, 9x3x40 = 1080 flats.

On average, Indian households have 5 members. Some apartments may be unoccupied. If assuming that 10% of apartments are unoccupied. So, the number of people living in the society will be 1080*0.9*5 =4860.

Q12. How do you fill 8 litres from 7 and 9-litre buckets?

Ans. Let us understand this step by step.

1. Fill the 7L bucket completely with water.
2. Pour the water from the 7L bucket into the 9L bucket. The 9L bucket now has 7L of water, and the 7L bucket is empty.
3. Fill the 7L bucket completely once again.
4. Carefully pour water from the 7L bucket into the 9L bucket until the 9L bucket is full. Since the 9L bucket already had 7L of water, it only needs 2L more to be full. So after this step, you will have 5L of water remaining in the 7L bucket.
5. Empty the 9L bucket completely.
6. Transfer the 5L of water from the 7L bucket to the 9L bucket. The 9L bucket now has 5L of water, and the 7L bucket is empty.
7. Fill the 7L bucket completely again.
8. Pour the water from the 7L bucket into the 9L bucket. Since the 9L bucket already has 5L of water, it can only take 4L more. This will leave you with exactly 3L in the 7L bucket.
9. Empty the 9L bucket completely once more.
10. Transfer the 3L of water from the 7L bucket to the 9L bucket. The 9L bucket now has 3L of water, and the 7L bucket is empty.
11. Fill the 7L bucket completely again.
12. Pour the water from the 7L bucket into the 9L bucket. The 9L bucket now has 3L + 7L = 10L, but since it can only hold 9L, you will have exactly 1L left in the 7L bucket.
13. Empty the 9L bucket completely.
14. Transfer the 1L of water from the 7L bucket to the 9L bucket. The 9L bucket now has 1L of water.
15. Fill the 7L bucket completely again.
16. Pour the water from the 7L bucket into the 9L bucket. The 9L bucket now has 1L + 7L = 8L of water.

Q13. How much paint will be required for painting a 20 m x 20 m wall?

Ans. Let us estimate the amount of paint required for every square meter. Now, we will find the area to be painted.

1. The wall to be painted will have the main area as 20 m x 20 m which is 400 square meters.
2. Let us assume that the depth is 1 mm.
3. We will also consider that the oil in half of the paint has dried after a few hours of the paint application on the wall.
4. Let us consider the width of the paint to be considered as 2 mm.
5. Thus, the volume to be painted is 400 square meters x 0.002 meters = 0.8 meters cube of paint is required.

Q14. Estimate the number of televisions sold in india every month. Show your assumptions & calculations in your answer along with the final number.

Ans. Let us start with the population of India since this is an official figure we know. Currently, there are 1.40 billion people in India. 

• Approximately 66% of the households own television in India.
• Most households have an average of 1.2 televisions.
• As an estimate, 231 million television sets are bought each year in India.
• On an everage, most televisions, be it an OLED, LED or LCD have an average lifespan of 10 years.
• Industry average for television replacement rate is 10%
• As an average, number of new households that are build every year is 0.5% of the total population

Now, let us come to the calculation part:

• Number of households owning television will be 0.92 billion.
• Number of televisions in each home 1.10 billion
• Average lifespan of a television is 10 years
• Approximate number of televisions that are replaced every year 1.10 billion x 10% = 110 million televions
• Average number of televisions replaced every month = 110 million/12 = 9.16 milliom  television
• Number of new household formed every year = 1.40 billion x 0.5% = 7 million households
• New television for the new households = 8.4 million households

Final estimate: 9.16 million + 8.4 million = 17.56 million televisions

Tips To Answer Guesstimate Questions

These are some of the sample guesstimate questions with answers for the interview. While answering any guesstimate question, you need to keep in mind the following points:

1. There is no definitive answer to such questions, only an educated guess.
2. Get clarity on the conditions expected by the interviewer for each question.
3. Create a flow to answer a question without trying to find a definitive answer.
4. Focus on the most factual information within a question to decide a flow in the question.
5. Determine the definitive or an approximate value that you already know so as to find the starting point to answer the question.