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Question

Which letter from among the given options, will replace the question mark (?) in the following series?
a, b, d, g, ?

This question was previously asked in
RRB NTPC 2019 CBT 1 Question Paper (8-Mar-2021) (Shift 2)
The correct answer is
k

Solving the Alphabet Series: a, b, d, g, ?

The goal is to identify the pattern in the given alphabet series and find the missing letter represented by the question mark (?). The series provided is: a, b, d, g, ?

Pattern Identification in the Series

Let's determine the position of each letter in the alphabet and find the difference between consecutive letters:

  • 'a' is the 1st letter.
  • 'b' is the 2nd letter. The difference between 'b' and 'a' is $2 - 1 = 1$.
  • 'd' is the 4th letter. The difference between 'd' and 'b' is $4 - 2 = 2$.
  • 'g' is the 7th letter. The difference between 'g' and 'd' is $7 - 4 = 3$.

The pattern observed in the differences between consecutive letters is an increasing sequence: +1, +2, +3.

Calculating the Next Letter

Following the established pattern, the next difference in the sequence should be +4.

  • The last letter given is 'g', which is the 7th letter.
  • Add the next difference (+4) to the position of 'g': $7 + 4 = 11$.
  • The 11th letter of the alphabet is 'k'.

Conclusion

Therefore, the letter 'k' replaces the question mark (?) in the series. This corresponds to Option 4.

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