Seven different numbers are selected from the integers 1 to 100, and each number is divided by 7. What is the sum of the remainders?
(1)The range of the seven remainders is 6.
(2) The seven numbers selected are consecutive integers.
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient. 答案选B，但我觉得不可以呀，1-100能被7整除的有：7、14、21......91、98一共14个数，从中选7个连续的不由很多种选法吗？例如：7、14、21、28、35、42、49； 14、21、28、35、42、49、56； 56、63、70、77、84、91、98等等很多种组合，这样的话the sum of the remainders答案就有很多种啊？大家觉得呢？或者我的推理有什么问题？
还有道概率题，想很久还是没想明白： Six cards numbered from 1 to 6 are placed in an empty bowl. First one card is drawn and then put back into the bowl; then a second card is drawn. If the cards are drawn at random and if the sum of the numbers on the cards is 8, what is the probability that one of the two cards drawn is numbered 5 ?
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发表于 2010-11-29 16:54:21
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