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

Find the missing letters for the given series from the given alternatives:
$.....abb......\,,....bb....a.....bbab.....ba$

Find out the wrong term from the given series:
$3, 10, 27, 4, 16, 64, 5, 25, 125$

Find out the wrong term from the given series.
$8, 13, 21, 32, 47, 63, 83$

Fill in the blank space for the given series with the correct alternative.
$24, 60, 120, 210, (...)$

Study the following arrangement carefully and answer the question given below:
$B, 2, I, J, K, 4, 3, H, 5, E, R, P, 6, N, A, 9, W, 8, T, U, 1, V, D, 7, F$
How many such numbers are there in the above arrangement,each of which is immediately preceded by a vowel and immediately followed by a consonant?