有两个在2到90之间（包含2与90）的整数，主持人请甲和乙两个数字逻辑分析高手猜这两个数。先同时告知甲乙双方：两个数的和大于11、两数的积小于260。再单独告诉甲这两个数的和，单独告诉乙这两个数的积。由甲乙轮流发言，请甲先说。
第一步，甲：我不知道这两个数，但我知道乙也不知道这两个数。
第二步，乙:一开始我不知道之两个数，但知道甲也不知道这两个数：现在我仍然不知道是哪两个数。（乙还有一句话：“无法判断甲现在是否知道是哪两个数”没有说出来。）
第三步，甲：我仍然不知道是哪两个数。
第四步，乙：哈哈！我知道是哪两个数了!
第五步，甲：哈哈，我也知道这两个数了！
请问：这是哪两个数?
有一个牢房，有3个犯人关在其中。因为玻璃很厚，所以3个人只能互相看见，不能听到对方说话的声音。”
有一天，国王想了一个办法，给他们每个人头上都戴了一顶帽子，只叫他们知道帽子的颜色不是白的就是黑的，不叫他们知道自己所戴帽子的是什么颜色的。在这种情况下，国王宣布两条如下：
1．谁能看到其他两个犯人戴的都是白帽子，就可以释放谁；
2．谁知道自己戴的是黑帽子，就释放谁。
其实，国王给他们戴的都是黑帽子。他们因为被绑，看不见自己罢了。于是他们3个人互相盯着不说话。可是不久，心眼灵的A用推理的方法，认定自己戴的是黑帽子。您想，他是怎样推断的?
【专题 GMAT逻辑题】
Maize contains the vitaminniacin, but not in a form the body can absorb. Pellagra is a disease thatresults from niacin deficiency. When maize was introduced into southern Europefrom the America in the eighteenth century, it quickly became a dietary staple,and many Europeans who came to subsist primarily on maize developed pellagra.Pellagra was virtually unknown at that time in Americas, however, even among peoplewho subsisted primarily on maize.
Whichof the following, if true, most helps to explain the contrasting incidence ofpellagra described above?
(A)Once introduced into southern Europe, maize became popular with landownersbecause of its high yields relative to other cereal crops.
(B)Maize grown in the Americas contained more niacin than maize grown in Europedid.
(C)Traditional ways of preparing maize in the Americas convert maize’s niacin intoa nutritionally useful form.
(D)In southern Europe many of the people who consumed maize also ate niacin-richfoods.
(E) Before the discovery of pellagra’slink with niacin, it was widely believed that the disease was an infection thatcould be transmitted from person to person.
