Facebook: 25 racehorses, no stopwatch, five tracks. Figure out the top three fastest horses in the fewest number of races.

脸谱网：25匹赛马；没有秒表；5条跑道。通过多少场比赛（最少）才能计算出跑得最快的前三匹马

Citigroup: What is your strategy at table tennis?

花旗集团：你玩乒乓球的战术是什么？

Google: You are climbing a staircase. Each time you can either take one step or two. The staircase has n steps. In how many distinct ways can you climb the staircase?

谷歌：设想一下你现在在爬楼梯，每一次你可以一次性登上一级或者两级台阶。楼梯的台阶有N个。请问，你有多少种直接方法可以爬到楼梯的最高处？

Gryphon Scientific: How many cocktail umbrellas are there in a given time in the United States?

Gryphon科技：全美的鸡尾酒里面配有多少把小花雨伞呢？