※ 引述《growthme (咖啡人)》之铭言： : 38. A financial investment club has *A* members with investment either : in bond or in stocks. *B* don't invest in either of them. *C* invest : in stock. *D* invest in bond How many people invest in both? : JJ 原题是不确定的数字 ABCD 是我自己假设的符号 : 所以想请问这题的思考方式有没有不正确 : A= either stock or bond : B= do not invest in either : C= stock : D= bond : 所以 BOTH= C+D-A : 以上问题麻烦大家了 我的想法和g大一样 either in bond or in stocks(A) = stocks + bond - both 所以 both = stocks + bond - A CD上有人认为either in bond or in stocks = only in bond + only in stocks 所以 A= stocks - both + bond - both both=(stocks + bond - A)*1/2 究竟是哪一个呢?? 拜托大家了 感恩 -- ＦＩＦＡ ＦＲＡＮＣＥ ＧＯＡＬ！ ★２００６ Ｗorld Cup 快让 Trezeguet 上场啦！ by mayeve --

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