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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

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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Important Resources to crack interviews (Mostly Free)

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Guesstimates for Data Science Interviews

Today is Day 14 and we all sharing 5 solved Guesstimates for Data Science Interviews. Case Studies and Guesstimates are asked in almost every Data Science interviews. Case Studies checks the business acumen of a candidate whereas Guesstimates check the logical and analytical thinking of the candidate. Following are a few solved Guesstimates for Data Science Interviews.

You can also explore Amazon Interview Question
We add 10 Interview Questions Daily – https://thedatamonk.com/daily-quiz/

You can also post your approach in each of the questions

Guesstimates for Data Science Interviews

Number of People wearing watches – https://thedatamonk.com/guesstimate-9-the-number-of-people-wearing-watches-in-bangalore/
Red Color Swift cars – https://thedatamonk.com/guesstimate-9-the-number-of-people-wearing-watches-in-bangalore/
Number of ambulances – https://thedatamonk.com/guesstimate-7-how-to-estimate-the-number-of-ambulances-on-the-road/
Estimate of Length of Road of your city – https://thedatamonk.com/guesstimate-4-estimate-the-total-length-of-roads-in-your-city/
Estimate of Area of an airport – https://thedatamonk.com/guesstimate-6-how-do-we-estimate-the-area-of-an-airport/
Number of Paan Shops in India – https://thedatamonk.com/guesstimate-3-how-many-paan-shops-are-there-in-india/
Number of Office Chairs in India – https://thedatamonk.com/guesstimate-1-number-of-office-chairs-sold-in-india/

The Data Monk Interview Books – Don’t Miss

Individual 50+ e-books on separate topics

Important Resources to crack interviews (Mostly Free)

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

Slot	Success Rate	Number of people giving money
6 AM – 10 AM	0.03	45
10 AM – 4 PM	0.01	15
4 PM – 10 PM	0.05	75
10 PM – 6 AM	0.006	9
		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

Slot	Success Rate	Number of people giving money	Amount
6 AM – 10 AM	0.03	45	94.5
10 AM – 4 PM	0.01	15	31.5
4 PM – 10 PM	0.05	75	157.5
10 PM – 6 AM	0.006	9	18.9
		144	302.4

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 9 : The number of people wearing watches in Bangalore

Ans: Let’s assume population of Bangalore as 10 million and the day today is a working day for every age group

And age group wise population assumption would be

0–15 yrs: 30%; 15–25 yrs: 20%; 25–50 yrs: 30%; >50 yrs: 20%

Income wise population would be

Above poverty line: 75%

The people below poverty has negligible chance to use a watch, so I am eliminating this 25% population from every age group.

Now we have 75% of aforesaid % in every age group. As below poverty is eliminated 0–15 group mostly have school children and infants I assume 5% of them wearing watches today. So the count would be 2.25 million*5%=112500

15–25 age group have majority of higher education students who spend most of their time using mobile phones, so people using watches may be nearly 25% which gives 1.5 million*25%= 375000

25–50 groups have professionals working somewhere for their survival whose generation recently entered the smartphone culture. So most of them use watches. If out of this group, if 90% are couples, we will approximately have 20% housewives in it. As there is less chance of housewives wearing watches we can neglect it. The remaining 80% population say 90% wear watches, then count would be (80%*2.25 million)*90%=1620000

Coming to >50 group say 25% are working somewhere having 90% of them wearing watches again and in remaining 75% let 20% wear watches as we see many of our grandfathers wearing watches even in house. So count would be (25%*1.5 million)*90%+(75%*1.5 million)*20%= 562500

Total= sum of all these
=2.67 million wear watches

Guesstimate 8 : How many red colour Swift cars are there in Delhi ?

Let’s start with the population of Delhi which is 2 Crores.

We will divide this population into two groups-

1. Family(80%) = 0.8*20000000 = 16000000 family members

2. Bachelors(Individuals) (20%) = 0.2*20000000 = 4000000

Number of families(assuming 4 members in each) = 16000000/4 = 4000000.

Guessing that 50% of families have cars, so the number of families with cars = 2000000.

In Delhi, we can assume that 25% of the families belong to high class society so they can afford 2 cars on an average and the rest can afford only one car.

Therefore number of cars with families 
= 0.25*2000000*2 + 0.75*2000000*1 
= 2500000.

Now let’s say only 10% of the individual population can afford a single car.

Therefore, number of cars with individuals 
= 0.10*4000000 
= 400000.

So the total number of cars in Delhi can be estimated as 
2500000+400000 = 2900000 
which can be rounded of to 3000000 for simple calculations.

Since Maruti being the Indian market leaders in car sector so we can safely assume 50% of cars on the roads of Delhi are of Maruti, i.e., 1500000 cars.

Swift is one of the most common and affordable models along with Alto, WagonR, Omni and 800. So let’s assume there are 200000 Swifts.

White, silver, grey, black are the most common colors. So
75%(approx) of Swifts will be of these colors.

Now we are left with 50000 Swifts of different colors. Considering red, yellow, blue, maroon and orange as possible other colors,we can guess that there are nearly 10000 red Swifts in Delhi.

Keep Learning 🙂

The Data Monk

Guesstimate 7 : How to estimate the number of ambulances on the road ?

Ans: Let’s start with the population of the country ~ 1.3 Billion (1300 million)

Rural – 70% = 900 million Urban 400 million

Let’s divide the Urban population into three groups based on income level – Low |High |Upper High

I would divide as : Low: 30% High - 50% Upper High - 20%
So Urban Low: 120 million High - 200 Upper High - 80 million

Now out of Urban Low I would assume 10% have driving as occupation (Rise of taxi services etc. (only considering 4 wheeler drivers))
= 12 million (120,00,000)

Out of these I would assume 1–1.5% are ambulance drivers = 120000

So we can say almost 1,20,000 ambulances are available in the country at any time.

Now generally ambulances are available on calling, that means, at least a half of them are always on backup. let’s assume that 70% of them are on idle at any given point of time.

Also since their average journey time is of 20–25 minutes,
so we can say not more than 10% of ambulances would be on road at any time

So we can say 10% are on roads at any time = 12000 ambulances on road across Urban India.

Guesstimate 6 : How do we estimate the area of an Airport ?

Ans: Let’s assume the airport can accommodate 10 planes at once and handle 5 runways.

Average length of runway = 2000m

Width of runway = 50 m

The total area of runway is 2000*50*5 = 500000 sq.m

Length of average plane is assumed as 50m and its wingspan is 40 m.

Total area of 10 planes = 20000+500000 = 520000 sq.m

Now somes assumptions, total area occupied by the building is equal to the area of runways and planes i.e 520000 sq.m

Total area of airport = 104000 sq.m.

There is a lot of empty space on an airport so we assume 40% of the total hence the final area is = 104000/0.6 = 1700000 sq.m.

You can think of different methods to calculate the same, this is just one of the quick way ti estimate the area of an airport

Guesstimate 5 : How much is the surf excel detergent usage in a day in India?

Approach:
India has a population of approx 1.2B People.

About 20% are BPL and would therefore not use surf excel. Remaining population: o.8*1.2B = 0.96B people.

Assuming a family of 4 people that is 0.24B families.

Rural:Urban = 30:70 (0.072B:0.168B)

Assuming only about 10% of people use surf excel in ruler areas, due to the availability of other cheaper mediums that will be 16M Families.

Due to competition and availability of substitutes in urban areas, assuming surf excel has a market share of 40%, that will be about 28M families.

Total user base: 44M Families.

Everyday usage must be at least 10 grams, total usage = 440 Million gms of surf excel everyday.

Guesstimate 4 : Estimate the total length of roads in your city

Approach:

If we take Mumbai and say Blue Dart, it will take 1 delivery truck for a region like Andheri from the regional distribution centre.

Andheri is assumed as approximately 25km^2 in area.

A delivery truck driver would work for 7 hours a day driving, at a speed of 30–40 kmph (Andheri being congested).

So kilometers he clocks in a day: 30*7 = 210 km.

Now generally the delivery schedule is planned in a such a way that all deliveries happen in the most efficient way. (Operations Guys at the firm would be getting paid lakhs for ensuring this shit!, but then technology rules! )

So assuming up and down journey, I would assume length of the roadways in Andheri area as 210/2 = 105 km.

But provisioning for some scope of redundancy during the travel, I would take 70% uniqueness factor.
That gives us ~ 70km

Also some of the areas would be covered by bike delivery
guys: say 30% of what truck covers (as bikers cover short distances) = ~20km

Also 10–15 km for postman/walker delivery personnel : ~
10km

So total road length for Andheri ~ 100km
Now, Mumbai city area: 600km^2
So Andheri like region = 600km^2 / 25 = 24
Assuming a coverage ratio of the courier service to be 90%
Regions covered: ~22

So total road length ~ 22*100 = 2200km.

Keep Learning 🙂
The Data Monk

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

Category: Guesstimate

Guesstimate – Annual income of a beggar in Bangalore

The Data Monk Interview Books – Don’t Miss

Important Resources to crack interviews (Mostly Free)

Guesstimates for Data Science Interviews

The Data Monk Interview Books – Don’t Miss

Important Resources to crack interviews (Mostly Free)

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

Guesstimate 9 : The number of people wearing watches in Bangalore

Guesstimate 8 : How many red colour Swift cars are there in Delhi ?

Guesstimate 7 : How to estimate the number of ambulances on the road ?

Guesstimate 6 : How do we estimate the area of an Airport ?

Guesstimate 5 : How much is the surf excel detergent usage in a day in India?

Guesstimate 4 : Estimate the total length of roads in your city

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

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