Guesstimate – Annual income of a beggar in Bangalore

Annual income of a beggar in Bangalore

Guesstimate is asked in an interview to understand the analytical understanding of the candidate as well as to check his thought/approach diversity.

Guesstimates can range from finding the number of ‘Red’ Cars in Delhi to the number of trees in Bangalore.

In one such interview, the candidate was asked to estimate the income of a beggar in Bangalore. We received 22 responses on this question, you can read their diverse approach or can write your own

Link to question – https://thedatamonk.com/question/how-much-is-the-annual-income-of-a-beggar-in-bangalore/

Annual income of a beggar in Bangalore

Link to the question with all the approach – https://thedatamonk.com/question/how-much-is-the-annual-income-of-a-beggar-in-bangalore/
If you have a different approach then please add your answer, else upvote the one which you like

Annual income of a beggar
Annual income of a beggar

First Approach – Ognish Banerjee

Assumption :
1. A beggar meets 100 people per day out of that chance of converting is 50%
2. The beggar knows where to search for people , let’s say near offices or tech park to have a better conversion rate
3. The beggar knows the peak time of the day as well as the peak time during the evening
4. The beggar starts his day from 10 am in the morning till 10 pm till night
5. Average income from a person is Rs 20

Now to go about this.

I’m categorizing the daily hour for wekkdays

10 am to 1 pm – peak time
1 pm to 5 pm – medium
5pm to 8 pm – peak
8pm to 10 pm – medium

Number of people he meets in these hours

10 am to 1 pm – 40 people
1 pm to 5pm – 10 people
5pm to 8pm – 40 people
8pm to 10pm – 10 people

On average expected income would be

(40*20) + (10*20) + (40*20) + (10*20) = 2000
5 days for weekdays = 10000
50% conversion rate = 5000

On weekdays in a month his income is = 5000 * 4 ( 4 weeks in a month) = 20000

Now taking the week ends. His strategy would be different. The beggar won’t be roaming near the offices, rather he would roam near the neighborhood during day and shopping mall/theatre during night.

If I go with similar calculation (not mentioned here) his evening income is way higher, peak time 6pm – 11pm

He meets 50 people with 20 rs each – 1000
50% conversion – 500
Number of weekends 8 – 500*8 = 4000

Total monthly income = 24000

Total annual income : 24000 * 12 around (3 lacs ) taking holidays, special events all around the year.

I’m a Mu Sigman also, during my first year I also earned the same like a beggar!!! Wow

Second Approach – Nilanjan Kumar

In the 24 hours time, let’s assume that a beggar sleeps 5 hours a day and also assume 5 hours he is busy doing other pieces of stuff like eating, playing cards on the roadside, etc. so that makes our time as: –

24-5-5 = 14 hours.

The beggar divided his time as below(5 days of working) : –
Time Interaction with People(per day) Conversion rate
6 a.m – 10 a.m 50 80%
12 p.m – 4 p.m 30 50%
6 p.m – 10 p.m 40 70%
11 p.m – 1 a.m 25 30%

Reasons for taking the conversion rate like this:
6 a.m. to 10 a.m – People in a good mood going to start their day by offering something to needy people.
12 p.m to 4 p.m. – People will be in a hurry as they have got limited time from the office.
6 p.m to 10 p.m – Back from work if a day went well they will offer to make each day good.
11 p.m to 1 a.m – End of the day.

If on average they get Rs. 5 from a single person, then: –

Time People offering money(per day) Amount(avg Rs 5 per person)
6 a.m – 10 a.m 40 200
12 p.m – 4 p.m 15 75
6 p.m – 10 p.m 28 140
11 p.m – 1 a.m 10 50
Total = Rs 465 per day

This 465 per day will be for 5 days a week as on weekends the time between 12 p.m. to 4 p.m and 6 p.m to 10 p.m will have conversion rates more. But on the contrary morning conversion rate will be less. So taking that situation into count, this Rs. 465 per day will increase to Rs. 500 per day (considering an average increase of Rs. 35 ).

Hence, Calculating for per week: –

(465*5)+(500*2) = Rs. 3325
A month has 4 weeks, hence income in 1 month = Rs. 3325*4 = Rs. 13,300
For annual income, 12 months, Hence, 12* 13300 = Rs. 1,59,600/-

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How much is the annual income of a beggar in Bangalore?

You can assume anything and everything under the Sun, just to try to keep the assumptions close to reality
I always start with an equation, for this question the equation which I assumed was:-

Amount per day * Number of Calendar Days (365)

Assumption 1- A beggar begs all day of the year
Now, I have divided a complete day in 4 parts
6 am to 10 am – High income
10 am to 4 pm – Low income
4 pm to 10 pm – High income
10 pm to 6 am  – No income 

Assumption 2 – The beggar will bet more money in slot 1 and 3
Assumption 3 – Beggar interacts with 500 people in each slot
Assumption 4 – The success ratio table

SlotSuccess RateNumber of people giving money
6 AM – 10 AM0.0345
10 AM – 4 PM0.0115
4 PM – 10 PM0.0575
10 PM – 6 AM0.0069
144

Assumption 5 – Probability of amount, I have safely assumed that 30% people will give Rs.2, 20% will give Rs.5 and 50% will give Rs.1

SlotSuccess RateNumber of people giving moneyAmount
6 AM – 10 AM0.034594.5
10 AM – 4 PM0.011531.5
4 PM – 10 PM0.0575157.5
10 PM – 6 AM0.006918.9
144302.4

Now we have Rs.302.4 per day income.
Annual amount = 302.4*365 =  Rs. 110,376 It doesn’t matter if the amount is high or low, what matters is that you have an approach to solve the problem. Few more things which you can add here are:-
1. Divide the year into seasons
2. Divide year into weekend and weekdays
3. Public Holidays

Keep Learning 🙂

Nitin Kamal

Guesstimate 3 – How many paan shops are there in India ?

Ans: We will use the method of Demand and Supply

Total population of India = 1.2bn or 1200 Mn

Male = 700 Mn & Female = 600 Mn ( 900 women per 1000 men )

The ratio of Female/Male for Pan consumption is very small.

Female in india those consume pan on regular basis = 2% = 600Mn*.01 -> 12Mn

Divide male on the basis of age groups :

0–15 ->  Neglect this section
16–22 -> 15% of 700Mn 
= 105Mn -> 5Mn ( This is the college age & as per my own college scenario 5 students consume pan out of the 100)
23–50 -> 35%of 700Mn
= 240 Mn -> 20% people consume -> .2*240 -> 48Mn
51–80 -> 20% of 700Mn
=140Mn -> older age, various problems like in teeth -> .05*140
-> 7Mn
Total demand of pan = 12+5+48+7 = 72 Mn

Using Supply :

Time taken to make 1 pan = 2min -> 30 in 1 hour

Lets pan shop opens for 10 hours -> 30*10 = 300 pan

Number of pan shops in India= 72 Mn/ 300 = 2,40,000 ~ 2.5 lakh

Guesstimate 2 – How many gmail users are there in India ?

Approach

The population of India is – 1,300,000,000 i.e. 1.3B
Internet penetration in India is – 30%

Assumed Population Distribution –

  • 0-20 : 25%
  • 21- 60 : 60%
  • >60 : 15%

People of age between 0-20 using internet
= 0.25*390000000
= 97500000
~100,000,000

Similarly people of age between 21-60 and >60 using internet will be 230,000,000 and 60,000,000 respectively.

Assumption

People of age 0-20 usually do not need an email account. But we may consider 5% of them do have it.

Therefore email users of 0-20 age group = 0.05*100000000 = 5000000.

The major proportion of email users are the employed people. Since in India employment rate is 75% but not all of them need an email account.

We will assume 75% of employed people use an email account.

Therefore email users of age 20-60 = 0.75*0.75*230,000,000 = 130,000,000(approx.)

Out of 60,000,000 people aged above 60, 25% of them use an email account. So email users of this age group = 0.25* 60,000,000 = 15,000,000.

So total email users in India = 5000000 + 130000000 + 15000000 = 150,000,000.

Gmail is a free and most prominent email service provider. So the nearly 85% of email users use Gmail.

Therefore number of Gmail users in India
= 0.85*150000000
= 127,500,000.

Practice Guesstimate

You already know that there are some 100 Million iPad being sold in India each year. But can you guess the area of an airport? Let’s say I need to know the total area of the Bangalore airport.

There are four important areas in an airport:-
1. Parking space
2. Sitting space
3. Hangar space
4. Runway

Let’s assume the following percentage:-
1. Parking space – 10%
2. Sitting space – 10%
3. Hangar space – 10%
4. Runway – 70%

Now, suppose that on an average 168 flights fly from Bangalore. That means per hour 7 flight will be on the runway, so we need 7 runways.

A flight runs for half a minute on the runway at a speed of 120 km/hr. Thus each runway will be 1 km long. There are 7 runways, thus 7 kilometers.

The parking space, hangar space, and sitting space is 10% each, thus it will have a total space of 3 kilometers.

The total area of Bangalore airport is 10 kilometers.

This is obviously just an estimation. You can choose other ways to do a similar calculation like below:-
1. Number of flight
2. Number of passengers to estimate the sitting space
3. The dimension of an airplane to get the length
4. Number of travelers to guess the number of cars and cabs to guess the area of the parking

We will keep updating the puzzle page with more guesstimate examples. Practice at least 10-15 problems to understand how to maintain consistency with the problem.

Few problems worth giving a shot are:-
1. Number of red cars in a city, say Mumbai
2. Number of people wearing yellow cloth on a Monday in Delhi
3. Number of people eating pizza right now
4. Revenue of Facebook/Amazon/Youtube
5. Number of beer bottles in India
6. Number of weddings in India/Spain/Timbuktur

Keep practicing 🙂

XtraMous


Guesstimate

Guesstimate is a methodological process of guess and estimate. Guesstimates have now become an important part of several Business Analyst/Data Scientist and MBA interview process.

What does a person asking you questions as absurd as “How many people are wearing red today?” is looking for ?
You know that he has no idea about the same but he has the power to select or reject your candidature. You will be judged entirely on the basis of your approach and the number of points which you can think of.

One and only one thing to keep in mind when you are solving a guesstimate question – You should start with a number and you have to be very very consistent with the same in the entire solution. And be very particular about your assumptions.

Let’s take an example:

What are the number of iPad sold in India in 2018?

Assumption 1 – Population of India is 1000 Million (though it’s 130 but you can safely assume a round of number of simple calculation and this is very much acceptable)

Assumption 2 – Population percentage below poverty line – 60%
and Population percentage of upper middle class 20%, whereas the rest 20% is the middle class. So there are 200 Million people who are financially eligible to buy an iPad.

Assumption 3 – Now take these 200 Millions as your base number. Dividing this 200 Million into Rural and Urban population:

Rural – 20% = 40 Million
Urban – 80% = 160 Million

Let’s divide the Rural and Urban population on the basis of age:

Rural Total population = 40 Million

AgePopulation
Percentage
Population
(Number)
Percentage buying
iPad
iPad Sold
0-12 YO10%4M0%0M
12- 20 YO30%12M30%3.6M
20-40 YO30%12M40%4.8M
40-60 YO10%4M10%.4M
60 + YO20%8M0%0M

Total iPad sold in Rural area = 8.8 Million

AgePopulation
Percentage
Population
(Number)
Percentage buying
iPad
iPad Sold
0-12 YO10%16M0%0.0M
12- 20 YO30%48M40%19.2M
20-40 YO30%48M80%38.4M
40-60 YO20%32M40%12.8M
60 + YO10%16M20%3.2M


Total iPad sold in the Urban area = 73.6 Million

Total iPad sold in India = 82.4 Million

This number might be very close or very off, but you took a couple of factors and successfully derived a number.

You can also take more factors like:-
1. Occupation – People working in Technical field are more inclined towards buying gadgets(Assumption)
2. High or low number of service center in a particular city – A city with more number of Apple service centers will sell more devices (Assumption)

With every new factor, your calculation will increase in complexity. So, add factors only if you think you can manage the calculation.

It’s always better to arrive at a number after 15 minutes of discussion with limited factors than arriving nowhere after 1 hour of intense discussion with a lot of factors.

If you want to practice more, you can visit this link

XtraMous