5, 7.5, 12.5, 22.5, ?

Select the combination of letters that when sequentially placed in the gaps of the given letter series will complete the series.
cd_ab_cd_abb_dda_b

Which letter-cluster will replace the question mark (?) to complete the given series?
DRBZ, ABKX, ?, UVCT, RFLR

In the following question, select the word which cannot be formed using the letters of the given word.
CAPABILITIES

Which letter-cluster will replace the question mark (?) to complete the given series?

MU, NE, PX, QF, SA, TG, ?

A series is given, a term is missing in series. Choose the correct alternative from the given ones that will complete the series.
I, V, ? , L

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.
DP, EY, FJ, ?

In the given word ‘MOTIVATION’ if the vowels are changed to the next letters and the consonants are changed to the previous letters as per the alphabetical series, then which letter/letters are repeated more than once?