7, 4, 14, 8, 21, 16, ( ), ( )

Loveyou2019-12-17  9

问题 7, 4, 14, 8, 21, 16, ( ), ( )

选项 A. 20, 18B. 28, 32C. 20,32D. 28, 64

答案B

解析隔项法,奇数项是以7为公差的等差数列,偶数项是以2为公比的等比数列,故答案为B。
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