# Verbal Reasoning →Series Completion → Alphabet Series: Question – 15

Find the missing term in the following series:
Z, X, S, I, R, R, ?, ?
[A]G, I
[B]J, I
[C]J, K
[D]K, M

G, I
In the above question, the pattern is
$Z\xrightarrow{\text{-2}}X\xrightarrow{\text{-5}}S \xrightarrow{\text{-10}}I \xrightarrow{\text{-17}}R \xrightarrow{\text{-26}} R\xrightarrow{\text{-37}}\textcircled{G}\xrightarrow{\text{-50}}\textcircled{I}$
We note that numbers representing the difference between the consecutive terms of the series again form a series – 2, 5, 10, 17, 26, 37, 50 – in which the pattern is +3, +5, +7, +9, +11, +13.