The sum of the first 50 positive integers is 1,275. What is the sum of the integers from 51 to 100, inclusive?

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问题 The sum of the first 50 positive integers is 1,275. What is the sum of the integers from 51 to 100, inclusive?

选项 A、2525
B、2550
C、325
D、3775
E、5050

答案D

解析 前50个正整数的和是1275,问从51至100的整数(包括51和100)的和是多少?
解:本题的正确答案为(D)。为简化计算,考生可把从51到100之间的整数拆开来计算:51=50+1,52=50+2,…100=50+50,由此可得:51+52+…100=50×50+(1+2+…+50)=3775
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本试题收录于: GRE QUANTITATIVE题库GRE分类
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