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

Study the following arrangement carefully and answer the question given below:
$R, 4, E, J, 5, T, 1, A, M, Q, 3, 8, N, I, K, 7, W, F, 6, D, 9, U, 2, Y, V$
How many such numbers are there in the above arrangement,each of which is immediately preceded by a consonant but not immediately followed by a consonant?

These questions are based on the following set of numbers.
$389 \quad 476 \quad 635 \quad 847 \quad 568$
Which number will be the smallest if the first and the last digits are interchanged in all the numbers?

Which is the number that comes next in the sequence:
$0, 6, 24, 60, 120, 210, ?$

Fill in the blank space for the given series with the correct alternative.
$1, 9, 17, 33, 49, 73, (...)$

How many such pairs of digits are there in the number $7326985$ each of which has as many digits between them in the given number as when the digits of the number are rearranged in ascending order within the number?