If the digits in the number $5, 7, 3, 4, 6, 2, 9$ are arranged in ascending order from left to right,how many digits will remain at the same position?

Study carefully the following arrangement of letters, digits and symbols to answer these

questions.

$M, 7 ,\&, 8, L ,P ,@ ,Q ,N ,\beta ,T ,Y ,3 ,2 ,= ,E ,\$ ,4 ,9 ,\#, G ,H ,5$

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

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

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?

Fill in the blank space for the given series with the correct alternative.
$3, 7, 15, 31, 63, (\dots)$

Choose the correct alternative answer

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