400K people use the train during peak time (between 7 am - 9 am) to go to downtown and the capacity of each train car is 200. it takes the train 45 min for a round trip to downtown. To calculate the number of train cars needed, can’t we divide the 400K / 200? Do we need to divide by the number of departures per train during peak?
Each train will be able to do 3 trips to downtown between 7 am and 9 am. So you will need 3 times fewer trains. 7-9 am is already peak time - you can assume any kind of distribution of passengers during those 2 hours.
Hi there,
As Agrim mentioned, you're forgetting travel time.
If you do just 400k/200 you're grossly overestimating the # of cars!
Very very important to consider multiple uses of trains here!
Hello!
To add on top of what has been commented on top, and precisely after seeing lately many posts like yours asking about market sizings, I have created a case that explains it step by step with an example
You can find it for free in PrepL's library in this link:
https://www.preplounge.com/en/management-consulting-cases/candidate-led-usual-style/intermediate/market-sizing-new-startup-launch-baby-strollers-in-the-us-244
Hope it helps!
Cheers,
Clara
Expert case by