1 + 2 + 3 + 4 + 5 + 6+-----+30=( )A. 475 B. 465 C. 455 D. 445
1 + 2 + 3 + 4 + 5 + 6+-----+30=( )
A. 475 B. 465 C. 455 D. 445
A. 475 B. 465 C. 455 D. 445
参考解析
解析:根据等差数列求和公式可知,该数列之和为(1 + 30) X 30/2 = 465,故选B。
相关考题:
What is the contra positive of the relation represented in the exhibit shown below?A.R= {1,2, 1,3,1,4,1,5}B.R= { 1,1,2,2,3,3,4,4,5,5}C.R= {2,1 ,4,1,2,2,1,3,3,2,1,4,4,4,5,4}D.R= {1,2,3,1,1,4,2,2,2,3,4,1,4,4,4,5}
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