The sum of the first 50 positive integers is 1,275. What is the sum of the integ

游客2024-01-12  4

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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