49 lines
1.0 KiB
Markdown
49 lines
1.0 KiB
Markdown
---
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id: 5900f4e01000cf542c50fff2
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title: 'Problem 371: Licence plates'
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challengeType: 5
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forumTopicId: 302033
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dashedName: problem-371-licence-plates
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---
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# --description--
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Oregon licence plates consist of three letters followed by a three digit number (each digit can be from \[0..9]).
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While driving to work Seth plays the following game:
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Whenever the numbers of two licence plates seen on his trip add to 1000 that's a win.
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E.g. MIC-012 and HAN-988 is a win and RYU-500 and SET-500 too. (as long as he sees them in the same trip).
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Find the expected number of plates he needs to see for a win. Give your answer rounded to 8 decimal places behind the decimal point.
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Note: We assume that each licence plate seen is equally likely to have any three digit number on it.
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# --hints--
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`euler371()` should return 40.66368097.
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```js
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assert.strictEqual(euler371(), 40.66368097);
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```
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# --seed--
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## --seed-contents--
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```js
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function euler371() {
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return true;
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}
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euler371();
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```
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# --solutions--
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```js
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// solution required
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```
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