题目

The arithmetic mean of the 5 consecutive integers starting with 's' is 'a'. What is the arithmetic mean of 9 consecutive integers that start with s + 2?

选项

A.

2 + s + a

B.

22 + a

C.

2s

D.

2a + 2

E.

4 + a

解析

对于数列\(s, s+1, …, s+4\),其平均数 = 中位数 = \(s+2 = a\) 因此,对于接下来的9个连续数\(a, a+1, a+2, …\),其平均数 = 中位数 = \(\frac{a + (a+8)}{2} = a+4\) 选E
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