Fill in the blanks with appropriate letters to complete the following letter series adkdadfkadfkd

Question

Fill in the blanks with appropriate letters to complete the following letter series

adkdadfkadfkd

1. A. c,f,c,f,c
2. B. c,f,c,d,c (Correct answer)
3. C. c,f,d,f,c
4. D. c,f,c,d,f

Correct Answer

Option B — c,f,c,d,c

Detailed Solution & Explanation

The correct answer is c,f,c,d,c.

Key Points

• The given series is: a__d__kda__dfk__a__dfkd
• The pattern is the six-letter block acdfkd repeated three times:
  • $\underbrace{a\,c\,d\,f\,k\,d}_{1} \;\; \underbrace{a\,c\,d\,f\,k\,d}_{2} \;\; \underbrace{a\,c\,d\,f\,k\,d}_{3}$
• Filling the blanks block by block:
  • Block 1: `a _ d _ k d` → the missing letters are c and f
  • Block 2: `a _ d f k _` → the missing letters are c and d
  • Block 3: `a _ d f k d` → the missing letter is c
• Reading the blanks in order gives c, f, c, d, c.

Shortcut Trick

• Count the total length first. The string holds 18 character positions, and 18 divides evenly by 6 — strongly suggesting a six-letter repeating block. Then find the block by reading the most complete run in the string, which here is `a_dfkd` in block 3, giving `acdfkd` immediately.

Additional Information

• Method for letter-series completion:
  • Write the string out with each position numbered, so the blanks are unambiguous.
  • Look for a repeating unit; its length usually divides the total number of positions.
  • Identify the unit from whichever repetition has the fewest gaps.
  • Fill every blank from that unit, then read the answers in the order the blanks appear.
• The commonest error is reading the blanks out of order or miscounting the underscores — note that in this question one gap is a double underscore in the printed paper, so counting positions carefully is essential.