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标题: Help, TT 10-4 [打印本页]

作者: plbl1510 时间: 2006-9-8 07:40
标题: Help, TT 10-4

If S is the sum of the reciprocals of the consecutive integers from 91 to 100, inclusive, which of the following is less than S?

I. 1/8

II. 1/9

III. 1/10

A.
None

B. I only

C.
III only

D.
II and III only

E. I, II, and III

作者: merryqing2004 时间: 2006-9-8 07:49

S ＝1/91+ 1/92+...+1/100

S > 1/100+ 1/100 + ...+1/100 = 10*(1/100)=1/10

S < 1/90 + 1/90 + ...+ 1/90 = 10*(1/90) = 1/9

1/10 < S < 1/9

III only

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