40,3,35,6,30,9,(),12,20,()
A.15,225
B.18,25
C.25.15
D.25,18

2023-05-26



参考答案:C

间隔组合数列。奇数项40,35,30,(25),20是公差为-5的等差数列;偶数项3,6,9,12,(15)是公差为3的等差数列。