45 lines
		
	
	
		
			1.1 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
		
		
			
		
	
	
			45 lines
		
	
	
		
			1.1 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
|   | --- | ||
|  | id: 5900f4551000cf542c50ff67 | ||
|  | title: 'Problem 232: The Race' | ||
|  | challengeType: 5 | ||
|  | forumTopicId: 301876 | ||
|  | dashedName: problem-232-the-race | ||
|  | --- | ||
|  | 
 | ||
|  | # --description--
 | ||
|  | 
 | ||
|  | Two players share an unbiased coin and take it in turns to play "The Race". On Player 1's turn, he tosses the coin once: if it comes up Heads, he scores one point; if it comes up Tails, he scores nothing. On Player 2's turn, she chooses a positive integer T and tosses the coin T times: if it comes up all Heads, she scores 2T-1 points; otherwise, she scores nothing. Player 1 goes first. The winner is the first to 100 or more points. | ||
|  | 
 | ||
|  | On each turn Player 2 selects the number, T, of coin tosses that maximises the probability of her winning. | ||
|  | 
 | ||
|  | What is the probability that Player 2 wins? | ||
|  | 
 | ||
|  | Give your answer rounded to eight decimal places in the form 0.abcdefgh . | ||
|  | 
 | ||
|  | # --hints--
 | ||
|  | 
 | ||
|  | `euler232()` should return 0.83648556. | ||
|  | 
 | ||
|  | ```js | ||
|  | assert.strictEqual(euler232(), 0.83648556); | ||
|  | ``` | ||
|  | 
 | ||
|  | # --seed--
 | ||
|  | 
 | ||
|  | ## --seed-contents--
 | ||
|  | 
 | ||
|  | ```js | ||
|  | function euler232() { | ||
|  | 
 | ||
|  |   return true; | ||
|  | } | ||
|  | 
 | ||
|  | euler232(); | ||
|  | ``` | ||
|  | 
 | ||
|  | # --solutions--
 | ||
|  | 
 | ||
|  | ```js | ||
|  | // solution required | ||
|  | ``` |