Guess Estimate Questions

Source : http://www.quora.com/Guesstimation-InterviewQuestions How do we guess/estimate the area of an airport? You can divide the airport area into three part, one the building(waiting room, airport control room), other one is runway and some open spaces. Buildings 10% Runway 40 % Open space 50 % Time spent by aeroplane during take off or landing is suppose 1 minutes and average speed on runway is suppose 120km/h so in 1 minute it will travel 2 km . So one runway length is 2 km and suppose there are 10 runways so 20 km. So runway is 20 km Hence open space 25 km Building 5 km Total 50 square km

How many golf balls can fit into a school bus? I am assuming the values of the size of the bus and golf ball here. Assuming the size of the bus to be 35 ft X 7.5 ft X 6.5 ft. The volume of the bus = 1706.25 cubic foot. 1 cubic foot = 1728 cubic inches Therefore, 1706.25 * 1728 = 2948400 cubic inches. Radius of golf ball = 0.85 inches. Volume of golf ball = 4/3 * pi * (radius^3) = 2.5 cubic inches. The number of golf balls that can be accommodated in the bus : 2948400/2.5 = 1179360.

Note: Assuming 25% of the space is occupied by the seats in the bus, that leaves us 75% of space to accommodate the balls. In such a case 

Total volume of bus available = 75% of 2948400 = 2211300



Number of golf balls that can be accommodated = 884520

Surf excel detergent usage in a day in India? Lets assume 70% population comes under non buyers of surf excel ( due to price sensitivity as other lesser price options are available. Rest 30% are those who can buy surf or expensive ones.. In this 30% only 15% will be using surf rest other expensive detergent like Ariel etc. So, total 15% of population. Per day avg consumption can be 10 grams. 1200000 * 0.15 * .01 = 1800 Kg aprx !!!

Estimate the total length of roads in your city." How would you go about answering this? Assume if your City Area is 6000 Sq KM's As per proper city guidelines atleast 30 % of the land should be roads. 6000 * 30 / 100 = 2000 Sq KM's are roads. Road is rectangular in shape. Assuming width of the road is around 40 mtrs. So the math is 2000*1000*1000 m*m / 40 m = 50000000 mtrs = 50000 Kms. I hope my math is correct!

How do I count the number of traffic signals in Delhi? How can the number of (pairs of) shoes sold online in Delhi through Flipkart in one day be estimated? Delhi Population = 18 million Considering the income pyramid, bottom 20% fall below poverty line, so won't buy online, Another 20% fall in the low income group, so we can discount them as well. Remaining 60% have the tendency to buy stuff online, so 60% of 18 million is 72 lakh.

Now internet penetration in India is 15%, on an average. But in Delhi, it is bound to be higher. Considering that we have already removed the bottom 40% of the population, the internet using population would be around 50% of the 72 lakh people, which becomes 36 lakh people. Of these 36 lakh people how many would be open to do online transactions? around 10% = 10% of 36 lakh = 3.6 lakh of these 3.6 lakh, how many would need shoes? On an average, men buy 2 shoes every year and women 4 (assuming) so, these 3.6 lakh people would buy 21.6 lakh (3.6* 6)shoes a year. In a single day how many shoes will be sold? -? 21.6lakh/365 Out of this number, what % of shopping will be done on Flipkart? = around 30% = 30% * 21.6/365 = ~1700 shoes How many people live in China? A billion. Because the population of China is young, a full 600 million of those inhabitants might be of child-bearing age. Half are women, so there are about 300 million Chinese women of childbearing age. Now, the average family size in China is restricted, so it might be 1.5 children, on average, per family. Let's say two-thirds of Chinese women have children. That means that there are about 300 million children in China. How many of those kids are under the age of two? About a tenth, or 30 million. So there are at least 30 million possible consumers of disposable diapers. To summarize: 1 billion people x 60% childbearing age = 600,000,000 people x 1/2 are women = 300,000,00 women of childbearing age x 2/3 have children = 200,000,000 women with children x 1.5 children each = 300,000,000 children x1/10 under age 2 =30 million children

How many shampoo sachets are sold in India in a year? india population:100 crore male female divided in ratio of 50:50 male :50Cr female:50Cr male: washes once in 2 days and uses 5 ml in each wash, so in a month 15X5=75ml is used, for an year=75X12=900ml so for 50cr=50crX .9 litre=4.5cr litre female: washes once in three days used 10ml of shampoo in each wash,so in a month 10X10=100ml is used , for an year=100X12=1.2L so for 50cr=50X1.2=6cr litre total shampoo used=10.5crL 70% is used in bottles and 30%in sachets ==10.5X30%==3.15crL~3crlitre each sachet is of 2 ml=3/.002=150cr

How many ping pong balls can fit into a 747? The 747-400 has a passenger volume of 876 cubic meters, plus a cargo volume of 159 cubic meters, for a total of 1035; using the same method as Jack, this gives about 22,870,000 ping pong balls: 103543π(.02)3⋅π18√≈22,870,000

A fully-fueled 747-400 filled with this many standard 2.7 gram ping pong balls would be too heavy to take off! This is a great example of how various design concerns (particularly the requirement for a round fuselage, as well as the need for aisles) result in airliners having more interior volume than they need - i.e., in reallife scenarios the payload is much more limited by weight than by volume. Ideally, the weight and volume limits would be reached simultaneously, since extra volume

translates into more surface area which translates into more skin friction drag, requiring more thrust and lowering fuel efficiency.

Estimate the number of office chairs sold in India"? The population of India is 1.2 billion= 1200 million. People are distributed in this form: 1. Metro cities- 200 million 2. Tier 1 cities- 300 million 3. Tier 2 cities- 300 million 4. Rural areas- 400 million 1- Around 50% of the people in metro cities are going to office for jobs. Number of office chairs used for them = 50/100 x 200 million = 100 million chairs 2- 30% of people in tier 1 cities would be involved in jobs. So Number of office chairs used in tier 1 cities = 30/100 x 300 million = 90 million 3- 20% of people in tier 2 cities would be involved in jobs/service. Number of office chairs used in tier 2 cities = 20/100 x 300 = 60 million 4- 10% of people in rural areas would be involved in Jobs. No. of office chairs used in rural areas = 10/100 x 400 = 40 million. Total number of office chairs sold in India = (100+90+60+40) million Ans = 290 million

How do you estimate the number of taxis (or auto rickshaws) in Mumbai (or any city)? since it is a metropolitan and a crowded city, thus we can assume that there are 5 taxi stands(from where the taxis operate) at an area of every 1 square km (guess). Also, as of today, it can be assumed that there is a 70:30 ratio in terms of cabs which are booked through taxi stands/roads to number of taxis booked online/apps/radio taxis(meru/ola/uber) as there presence is less as of now. Thus, say every taxi stand has (on an average) 8 taxis.

Also assume that the number of taxis leaving the city= number of taxis entering the city So Total Taxis per square km= 5*8= 40 Area of Mumbai = 600 sq km (approx) Thus total number of taxis= 600*40 = 24000 taxis So 70:30 :: 24000:x Thus on solving this we get x(i.e number of radio taxis) = 10500 (approx) Thus total number of taxis in Mumbai = 24000 + 10500 = 34,500 +/- 10%(error)

How many luxury watches with price greater than 50000 are sold in India? India population=130 cr(ass=100 cr) 2% of india is rich,ie,earns above rs30 lakh ass=income levels