Estimate the number of spark plugs in the state of California.

Question

Simax · Accepted Answer

In fact the number is much larger than that.
The average number of sparks per vehicle (in CA) is probably closer to 5.5. Four-cylinder vehicles are the norm in Europe, but in the US is common to see a higher percentage of V6 and V8 engines. For every gas (not diesel, as noted previously) vehicle in CA, working or not, you could estimate ~5.5 sparks.
In addition, you have to account for all stored (i.e. not necessarily installed in vehicles) sparks. So if there are, say, 20k car shops in CA and each of them holds 100 sparks in stock, that's another 2M sparks.
How about motorbikes? Probably 2.5 sparks on average?
Any spark factories in CA? Finished product would count too.
How many unsold/retired vehicles?
I'd say the final number is well north of 100M.

me · Answer

one spark plug per cylinder in an IC combustion engine running on petrol (gas)
diesel engines are compression ignited, so no spark plug.
with the above two refine market sizing

spark plugs aren't just for cars · Answer

Cars, lawn mowers, edgers, and many other engines.  Only going by cars is a huge underestimate.

JaySwami · Answer

This is a fermi question. assuming there is one sparkplug per vehicle, and the number of sparkplugs used in other machinary pales in comparision to the number of vehicles in california, then you just need to get the ball park figure for the number of vehicles..
here's my shot at it.. 
CA population is roughly 40 million. I would estimate roughly 1 car per family.. so lets say about 15-20 million cars in CA (taking into account children). so ball park figure of 20 million. lets add 10 million more for commercial vehicles, motorcycles,trailers etc.. .
I would estimate a total of 30 million spark plugs in the state of California.

Anonymous · Answer

This type teaser is no longer used. They said answering brain teasers well has no correlation with future job performance. Rather they might modify this question to relate it to the role you are interviewing for.

Google

Google interview question

Interview Answers

Want the inside scoop on your own company?

Bowls

Followed companies

Job searches