Number Series Questions

This is an alternating series in alphabetical order. The middle letters follow the order ABCDE. The first and third letters are alphabetical beginning with J. The third letter is repeated as a first letter in each subsequent three-letter segment.

By trial and error method from the given options,

'1' satisfies the above given equation.

Because the letters are the same, concentrate on the number series, which is a simple 2, 3, 4, 5, 6 series, and follows each letter in order.

The given number series is 2, 3, 7, 16, 32, ?

$$\begin{gathered} 2 \\ 2 + 12 = 3 \\ 3 + 22 = 7 \\ 7 + 32 = 16 \\ 16 + 42 = 32 \\ 32 + 52 = 57 \\ \end{gathered}$$

Hence, the next number in the given number series is 57.

The given number series is  21 56 102 160 231 316

21      56       102        160      231       316         416

   +35    +46       +58       +71      +85       +100

        +11      +12       +13      +14      +15

Hence, the next number in the given number series is 316 + 100 = 416.

The given number series 9, 19, 21, 43, 45, ... follows a pattern that

ALternately (x 2 + 1) and  (x 1 + 2)

9 

9 x 2 + 1 = 19

19 x 1 + 2 = 21

21 x 2 + 1 = 43

43 x 1 + 2 = 45

45 x 2 + 1 = 91

Hence, the next number in the given sequence is 91.

In this series, the third letter is repeated as the first letter of the next segment. The middle letter, A, remains static. The third letters are in alphabetical order, beginning with R.