The next term in the series ABD, DGK, HMS, MTB, .......... is :
2017
The next term in the series ABD, DGK, HMS, MTB, .......... is :
Answer: B. SBL — Concept — In an alphabet series each term is a block of letters. Replace every letter by its position in the English alphabet (A = 1, B = 2, … , Z = 26) and…
- A.
NSA
- B.
SBL
- C.
PSK
- D.
RUH
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Correct answer: B
Concept — In an alphabet series each term is a block of letters. Replace every letter by its position in the English alphabet (A = 1, B = 2, … , Z = 26) and read each letter-slot of the block as a sequence of its own. If a value runs past 26, keep counting round the alphabet by subtracting 26.
Application — Writing the four given terms as triples of positions:
Term | 1st letter | 2nd letter | 3rd letter |
|---|---|---|---|
ABD | A = 1 | B = 2 | D = 4 |
DGK | D = 4 | G = 7 | K = 11 |
HMS | H = 8 | M = 13 | S = 19 |
MTB | M = 13 | T = 20 | B = 28 (2 + 26) |
Now read each column on its own:
First letters: 1, 4, 8, 13. The gaps are +3, +4, +5, so the next gap is +6 and the next value is 13 + 6 = 19, which is S.
Second letters: 2, 7, 13, 20. The gaps are +5, +6, +7, so the next gap is +8 and the next value is 20 + 8 = 28. As 28 runs past 26, subtract 26 to get 2, which is B.
Third letters: 4, 11, 19, 28. The gaps are +7, +8, +9, so the next gap is +10 and the next value is 28 + 10 = 38. Subtracting 26 gives 12, which is L.
Reading the three results in order gives S, B, L — the block SBL.
Cross-check — The same block can be reached by a second, independent route: the steps inside each block. Within ABD they are +1 and +2; within DGK, +3 and +4; within HMS, +5 and +6; within MTB, +7 and +8. The fifth block must therefore have internal steps +9 and +10. Starting from S = 19: 19 + 9 = 28, and 28 − 26 = 2, which is B; then 28 + 10 = 38, and 38 − 26 = 12, which is L. Both routes give SBL.