What will be the missing term of the series?
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What will be the missing term of the series? E23K, F21M, G19O, ____, I15S
Show answer & explanation
Answer: D. H17Q
The series follows three independent patterns: (1) Letters increment alphabetically: E→F→G→H→I. (2) Numbers decrease by 2: 23→21→19→17→15. (3) Letters increment by 2 positions in the alphabet: K→M→O→Q→S. The missing term combines the 4th position of each pattern: H (4th letter), 17 (4th number), Q (4th letter in the sequence).
Step-by-step Derivation:
Analyzing each component:
Letter Position 1 (Alphabetic sequence):
- E (5th), F (6th), G (7th), ?, I (9th)
- Pattern: +1 each step
- Missing: H (8th) ✓
Middle Number (Decreasing sequence):
- 23, 21, 19, ?, 15
- Pattern: -2 each step
- 23 - 2 = 21
- 21 - 2 = 19
- 19 - 2 = 17
- 17 - 2 = 15 ✓
- Missing: 17
Letter Position 2 (Alphabetic sequence with step +2):
- K (11th), M (13th), O (15th), ?, S (19th)
- Pattern: +2 positions each step
- K (11) + 2 = M (13)
- M (13) + 2 = O (15)
- O (15) + 2 = Q (17)
- Q (17) + 2 = S (19) ✓
- Missing: Q
Conclusion: Combining all three patterns: H + 17 + Q = H17Q (Option D)