Choose the correct alternative answer

$adb...ac...da...eddeb...dbc...cbda$

Fill in the blank space for the given series with the correct alternative.
$6, 15, (\ldots), 45, 66, 91$

Find out the wrong term from the given series.
$2, 5, 10, 50, 500, 5000$

Choose the correct alternative to complete the series:
$...baa...aab...a...a$

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

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

How many such numbers are there in the above arrangement which are not immediately followed by a symbol and also are immediately preceded by a consonant?

To answer these questions study carefully the following arrangement of letters, digits and symbols.

$6, =, C, E, 3, 8, G, L, M, 7, \star, @, P, R, 4, \#, \$, N, T, 5, S, V$

How many such symbols are there in the arrangement each of which is immediately preceded by a number?