|
gdw-8-9，If an integer n is to be chosen at random from the integers 1 to 96, inclusive, what is the probability that n(n + 1)(n + 2) will be divisible by 8? A.1/4 B. 3/8 C. 1/2 D.5/8 E.3/4
我的想法是，把n(n + 1)(n + 2)展开得到n^3+3n^2+n 所以推导出n要是2的倍数，但和答案不符合
gdw-8-11 If n and k are positive integers, is n divisible by 6? (1) n = k(k + 1)(k - 1) (2) k – 1 is a multiple of 3. 想不明白为何选a，原理为何？ gdw-8-29 The annual rent collected by a corporation from a certain building was x percent more in 1998 than in 1997 and y percent less in 1999 than in 1998. Was the annual rent collected by the corporation from the building more in 1999 than in 1997? (1) x > y (2) xy/100 < x – y
答案选b，实在证明不出来，高手亲赐教，谢谢
| 
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2008-9-24 13:19:00
楼主
