What is Guesstimate ?

Guesstimate is an estimate based on a mixture of guesswork and calculation.

Now a days Guesstimates have become an important part of consulting/Analytics firm's interview processes and B-School competitions.

There is no exact answer to it, it is all about taking the right assumptions and solving them with proper logic.

Let us solve an Guesstimate question which I encountered recently !

Question: HOW MANY BLUE CARS ARE THERE IN DELHI?

Solution:

1. Let us assume Delhi population as 2 crores = 20000000
2. Lets consider every family has 4 members, so No of families in Delhi = 20000000/4
3. No of families in Delhi = 5000000
4. Lets assume 60% of the families own car = 5000000*60% = 3000000

Some families might have more than 1 car, so let us make some assumption on number of cars per family

1. Lets assume 75% own 1 car = 3000000*75% = 2250000
2. Lets assume 24% own 2 cars = 3000000*24% = 720000
3. Lets assume 1% own 3 cars = 3000000*1% = 30000
4. Based on the above assumptions, Total cars in Delhi = (2250000*1)+(720000*2)+(30000*3) = 3780000
5. Total Cars = 3780000

Lets assume

• Black, Red, White and Gray color cars contribute 20% each,
• Blue color cars contribute 10% and other Color cars contribute remaining 10%

Hence, number of Blue cars in Delhi = 3780000*10% = 378000 !!!!?