Which of the following numbers will replace the question mark (?) in the given series?

1, 3, 6, 18, 36, 108,?

In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it ?
MN_O_NN_M_NO

Select the option that represents the letters that, when placed from left to right in the following blanks, will complete the letter series.
_ V J R W B _ _ R W B V L _ _ B V _ _ W

Select the option that will fill in the blank and complete the given series.
DXB, GSI, JNP, MIW,___

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
5, 11, 21, 43, 85, ?

Which of the following numbers will replace the question mark (?) in the given series?

29, 33, ?, 113, 369

A series is given with one term missing. Choose the correct option from the given ones that will complete the series.

512, 256, 128, ?, 32, 16, 8

In the following options, select the number which will replace the question mark in the following series.
4, 2, 2, 3 , 6,?