ij130063

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622

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If the person who posted the 6 cars in 3 lanes problem (august 2019) is still looking for an answer, I have it.

We count the number of ways that some lane can be left empty, and subtract from the total:
Each driver has three choices, so it's .
Now, we count the ways where at least 1 lane is left empty:
But we have double-counted the read more ..

ij130063 Jan 10, 2020