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whycombinetortoday at 1:06 AM2 repliesview on HN

Denver has this... nominally. 3 machines (2 in circulation, one is a "Display"). 4 week checkout period. 103 current holds. 103*4/2/12 ≈ 17 year wait time.


Replies

wafflemakertoday at 7:38 AM

In the equation there seems to be a typo;

103 - number of ppl in queue, 4 - up to X weeks per person, 2 - number of machines 12 - ??

Maybe you initially wanted to use full months for how long a person can hold an item, but then switched to weeks, and accidently still used number of months to get the number of years?

Anyway, for an imprecise number, you can do with months - 104*1/2/12 ~4.3y.

For more precise result, use seconds, as that's the unit used for the precise length of the year. Year is not 365 days. It's actually longer, quoting Wikipedia for (tropical) year,

> Approximately 365 solar days, 5 hours, 48 minutes, 45 seconds

That gives

  104 * (4 * 7 * 24 * 60 * 60) /2 /(((365 * 24 + 5) * 60 + 48) * 60 + 45)
Which results in 3.986 years. At maximum. Much less than 17!

Edit: getting asterikses * right

dhosektoday at 2:06 AM

That theoretical wait time doesn’t usually end up being so long. Between borrowers returning things early, people on the wait list giving up and most importantly, the library deciding that the current inventory is insufficient, the wait times usually are much less than that (I’ve observed this with books and other materials at my local library and the wait on in-demand times is never as long as the queue would imply).

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