How many such digits are there in the number $52361984$ each of which is as far away from the beginning of the number as when the digits are rearranged in ascending order within the number?

Find out the missing letters for the given series from the given alternatives.
$adb.....ac.....da....cddcb.....dbc....cbda$

Choose the correct alternative for the missing term in the series: $2, 6, 12, 20, 30, ?$

Find out the wrong term from the given series.
$11, 5, 20, 12, 40, 26, 74, 54$

Study the following arrangement carefully and answer the question given below:
$R, 4, E, J, 5, T, 1, A, M, Q, 3, 8, N, I, K, 7, W, F, 6, D, 9, U, 2, Y, V$
Which of the following is exactly in the middle between $A$ and $D$ in the above arrangement?

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 vowels are there in the above arrangement, each of which is immediately followed by a symbol?