Back-of-envelope estimate of a school bus's weight, with a sanity check

In a product manager interview you are asked to estimate how much a school bus weighs. Reason out loud: clarify exactly what is being weighed, break the problem into pieces you can estimate, do the arithmetic, and check that your final number is believable. ```hint Anchor on something you know You probably have a feel for what a family car weighs. You can scale up from it, or add up the bus's major parts; doing both gives you a way to check yourself. ``` ### Clarifying Questions - Which kind of bus: a full-size school bus, or a smaller one built on a van chassis? - Should the bus be weighed empty, or with a driver, children and a full fuel tank? - Are we picturing the yellow school buses common in North America, or the coaches used for school trips elsewhere? - Should the answer be in kilograms or pounds, and is a range acceptable? ### What a Strong Answer Covers - Clarifying the bus type and whether passengers and fuel count before estimating. - A clear structure, such as a breakdown into components or scaling from a vehicle whose weight you know, with every input stated as an assumption. - Correct arithmetic with round numbers that the interviewer can follow. - A second method or reference point to sanity-check the result, ending with a range and units. ### Follow-up Questions - How much heavier is the bus when it is full of children? - Which assumption moves your answer the most, and how would you narrow it down? - How would your estimate change for an electric school bus?