MathLabs

第4题

A magician has one hundred cards 数ed 11 到 100100. He puts them in到three boxes, red, white 且blue, 每个nonempty. A member selects two boxes, chooses one card 从each, 且announces their 和. Given th是和, magician identifies box 从which no card was chosen. How many assignments 的cards 到three boxes make th是always possible?
第 4/5 步：译文：Classify equality
上一步下一步
A,B,C are common-difference progressions or two are singletons.A,B,C\text{ are common-difference progressions or two are singletons}.
详细分析

The equality characterizati上gives these two cases.