[求助][讨论]几道资充题请教!

fernandochang

都是ETS真题! 拜托请解释! X 3 8 Y Z 48. In the figure above, are the sums of the 3 numbers along each diagonal equal? (1)z=3 (2)y-x=0 A):C [F.33, Q.7] 57.If S is an infinite set of real numbers, is there a number in S that is less than every number in S? (1)Every number in S is an integer. (2)Every number in S is positive. A):C [F.25. Q.24] 59. 4 dollar amounts, w, x, y, and z, were invested in a business. Which amount was greatest? (1)y[此贴子已经被作者于2003-7-14 19:13:36编辑过]

fengqiwu

48、对角线的数字和相等，应有有y+3=x+z.条件z=3和x=y单独都不足以满足，但是综合条件1、2则有y+3=x+z.所以选c 57、我觉得选b，条件1负整数和正整数都有的无限数列，无法判断有无小于每个number的数，而条件二中，整数0满足 58、条件1不知w的大小，条件2单独也不能找出最大的，但是，综合1，2，x占25%，其余占75%，又有y25%,所以，w is the greatest

northying

57.C (integer and positive) is necessary, e.g.: 0.0001<0.001

fengqiwu

3x

fernandochang

第57题可否详细解释?   依然不懂!