Murphy's
Law of Queues
The line next to you will usually finish first.
On average the lines all move at the same rate-each being equally
likely to suffer from random delays that occur when the cashier has to
change the cash-register tape or when a customer wants to use a check
to
buy a pack of gum.
When we go to the grocery store we don't think about all of this,
instead we just want our line to finish first. In that case, the
chances that we've picked the line that will turn out to be one that
doesn't have any problems is just 1/N, where N is the total number of
lines in the grocery store.
If only concerned with beating the lines on either side of ours, the
chances we'll do so is only one in three. Only two thirds of the
time, either the line on the right or the line on the left will beat
ours.
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