一道比較動(dòng)腦子的數(shù)學(xué)題
一個(gè)盒子里放了一些球,每個(gè)球不是黑色就是白色,在盒子外面也放了一些球,用來做游戲.
我們從盒子里拿出任意2個(gè)球,如果它們的顏色一樣,就把它們?nèi)恿?從盒子外面的球里拿一個(gè)黑色的球放進(jìn)去.如果它們的顏色不一樣,那么把白球放回盒子里,把黑球扔了.按照這種玩法,盒子里的球每次會(huì)減少一個(gè),直到盒子里只有一個(gè)球時(shí),游戲結(jié)束.
游戲開始時(shí),盒子里有21個(gè)白球和32個(gè)黑球,當(dāng)你用上面的方法玩游戲,你能確認(rèn)那最后一個(gè)剩下來的球的顏色嗎?
英文原文
Consider an urn filled with a number of balls,each of which is either black or white.There are also enough balls outside the urn to play the following game:
We take any two balls from the urn.If they both have the same colour,throw them away but put another black ball into the urn.If they have different colours,then return the white one to the urn and throw the black one away.Each execution of the above process reduces the number of balls in the urn by one; when only one ball is left in the urn,the game is over.
Initially,there are 21 white balls and 32 black balls in the urn.Can you determine the colour of the last ball when you play the game?Justify your answer.
把思考的詳細(xì)過程給我下 我想理解