Fill in the blank space for the given series with the correct alternative.
$1, 2, 3, 6, 9, 18, (...), 54$

Fill in the blank space for the given series with the correct alternative.
$134, 245, 356, 467, (...)$

Choose the correct alternative to complete the series: $........babbba...a........$

In the arrangement $P, 2, 6, M, 9, K, S, 4, V, 7$,the positions of the $1^{st}$ and the $6^{th}$ elements are interchanged,those of the $2^{nd}$ and the $7^{th}$ are interchanged,and so on. Then,which of the following will be the $4^{th}$ element from the left end in the new arrangement?

These questions are based on the following set of numbers.
$738, 495, 329, 653, 849$
If $1$ is added to the first digit of each number and $1$ is subtracted from the second digit,which number will be the largest?

Find the missing letters for the given series from the given alternatives:
$b....ac....cc....cb...ab....ac$