70 lines
1.2 KiB
Markdown
70 lines
1.2 KiB
Markdown
---
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id: 5900f4e01000cf542c50fff2
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challengeType: 5
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title: 'Problem 371: Licence plates'
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forumTopicId: 302033
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---
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## Description
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<section id='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.
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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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</section>
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## Instructions
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<section id='instructions'>
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>euler371()</code> should return 40.66368097.
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testString: assert.strictEqual(euler371(), 40.66368097);
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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function euler371() {
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// Good luck!
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return true;
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}
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euler371();
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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// solution required
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```
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</section>
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