You can expect to have 3 types of market sizing questions:
1) Top down market sizing questions
- Calculate the number of gas stations in the US
- Calculate the size of credit cards market in the US
- How much domestic trash is collected each year in the US (in m3 or tons)?
2) Bottom up market sizing questions
- You know that Citi bank has a portfolio of 200 bln credit cards in x country. Calculate the size of the market
- You know that there are 40 tube stations in the Centre of Moscow. Calculate the number of Starbucks cafes in Moscow
3) Guesstimate questions
- If all the humans in the world were crammed together, how much area would we require? Compare this to the area of a large city, a state or a small country, the US, Asia
- How many golf balls would it take to circle the Earth at the equator?
I have answered a similar question and provided a detailed solution to a market size.