I had a doubt about the fun fact here - can someone please explain with an example of how to find numbers of ns in a factorial when the n is not prime i.e. how to find number of 15s in 100! ?

Thanks for the reply! So for finding the number 15s, do I find the number of 3s and 5s and then multiply these?

Actually the minimum - can you see why?

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Yes I think it’s the same logic as finding the number of trailing zeros in a factorial - where we find the number of 5s (since there might be many other 2s that don’t make up 10), so here we would take the minimum of number of 3s and 5s. Hope this is correct, thanks!!

How can I find the limiting factor? I mean how can I be sure 3 or 5 is limiting in 15!?

What do you think?

actually I donot want to think…I want to follow a process. and what should be the process?