The following question is based on the five three-digit numbers given below:
$519, 368, 437, 246, 175$
Which of the following is the third digit of the second highest number?

Find the wrong number in the series:
$7, 28, 63, 124, 215, 342, 611$

Fill in the blank space for the given series with the correct alternative.
$6, 11, 21, 36, 56, (\ldots)$

Choose the correct alternative to complete the series: $b _ a c _ c c _ c b _ a b _ a c$

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?

Choose the correct alternative to complete the series: $aa . . ab . . . . . . aaa . . . a$.