Fill in the blank space for the given series with the correct alternative.
$165, 195, 255, 285, 345, (...)$

Study the following arrangement carefully and answer the questions given below:

$7, R,E,T ,4 ,A ,9 ,\% ,D,F, 1, U, \# ,B ,@ ,8 ,H,I ,$©$, W,M, \star, 3,2 ,V ,\$ ,5 ,N,P,6, Q$

How many such consonants are there in the above arrangement, each of which is immediately preceded by a consonant and immediately followed by a number?

These questions are based on the following arrangement. Study it carefully and answer the questions.

$J ,\star, R, 3, P,L ,2 ,\# ,I,N, 7, O,C, @ ,K, 5, D, =, M, \$, 6, B, > ,A ,Q ,4$

If the above arrangement is written in reverse order, which element will be eleventh to the left of sixteenth from the left?

Fill in the blank space for the given series with the correct alternative.
$2, 6, 12, 20, 30, 42, 56, (\ldots)$

Fill in the blank space for the given series with the correct alternative.
$840, 168, 42, 14, 7, (...)$

Find out the missing letters for the given series from the given alternatives.
$a....abbb...ccccd.....ddccc.....bb....ba$