以下是引用edmund_zh在2008-7-13 20:39:00的发言:题目中有条件a是整数且>1,所以当a=2的时候,k是6,即k的最大值。k=5的时候a不是整数,k有必须>3,那么k只可能是4了,而且这个时候a恰好为4。所以综合条件1和2可以得出k为4 because a is a number more than or equal to 1 , so a could be equal to 2, so k could be equal to 6 . i can't rule out the possibility of 6 as the value of k. how to explain WHY k could not be 6? ( in another word, why a could not be 2?) and if k could be 4 or 6, i think the answer should be E, for two solution can not be determinded. |