Railway RRB Group D Number & Alphabet Series 2026 & 2027
संख्या और वर्णमाला श्रृंखला | Short Tricks + 60 Solved Q&A Hindi
RRB Group D · NTPC · ALP · RPF — Arithmetic, Geometric, Fibonacci, Alternating, Wrong Term, Missing Term — सभी Types + Short Tricks हिंदी में।
WhatsApp चैनल में
अभी जुड़े !!!
Telegram Group में
अभी जुड़े !!!
➕ Arithmetic Series
✖️ Geometric Series
🔁 Mixed Series
❌ Wrong Term
❓ Missing Term
🔤 Alphabet Series
HOT Short Tricks 2027
📢 Exam Pattern: Railway Group D Reasoning में Series से 5–8 Questions आते हैं — सबसे ज़्यादा! Pattern देखो, 30 सेकंड में Solve करो।
🏃 Railway RRB Group D Number & Alphabet Series Marathon 2027:
Part 1: Arithmetic Series (AP) | Part 2: Geometric Series (GP) | Part 3: Squares & Cubes Series | Part 4: Fibonacci & Alternating Series | Part 5: Mixed/Complex Series | Part 6: Wrong Term Series | Part 7: Two-tier Series | Part 8: Alphabet Series | Part 9: Alpha-Numeric Series | Part 10: Number-Letter Mixed | Part 11: Final Tricks
Part 1: Arithmetic Series (AP) | Part 2: Geometric Series (GP) | Part 3: Squares & Cubes Series | Part 4: Fibonacci & Alternating Series | Part 5: Mixed/Complex Series | Part 6: Wrong Term Series | Part 7: Two-tier Series | Part 8: Alphabet Series | Part 9: Alpha-Numeric Series | Part 10: Number-Letter Mixed | Part 11: Final Tricks
📌 Series के सभी Types — पहचानना सीखो
| Type | Pattern | Example |
|---|---|---|
| Arithmetic (AP) | Same difference (+/−) | 3,7,11,15,19 (+4) |
| Geometric (GP) | Same ratio (×/÷) | 2,6,18,54 (×3) |
| Squares | n² | 1,4,9,16,25,36 |
| Cubes | n³ | 1,8,27,64,125 |
| Prime | Prime numbers | 2,3,5,7,11,13 |
| Fibonacci | पिछले 2 का Sum | 1,1,2,3,5,8,13 |
| Alternating | Two series merge | 1,10,2,20,3,30,4 |
| Increasing Diff | Diff बढ़ती है | 1,2,4,7,11,16,22 |
| Decreasing Diff | Diff घटती है | 25,19,14,10,7,5 |
| Two-tier | Diff खुद एक Series | 1,3,7,13,21 (diff=2,4,6,8) |
🧠 Series Solve करने का Master Approach
Step 1: First Differences निकालो (consecutive terms का diff)Step 2: यदि diff constant → AP | यदि diff ratio → GP | यदि diff बढ़ रहा → Two-tier
Step 3: Second Differences निकालो (diff of diff) → Pattern दिखेगा
Step 4: Squares/Cubes check करो (1,4,9,16 या 1,8,27,64)
Step 5: Even/Odd positions separately देखो (Alternating Pattern)
➕ Part 1: Arithmetic Series (समांतर श्रृंखला)
Q1HOT 5, 11, 17, 23, 29, ___?
Differences: 6, 6, 6, 6 → Constant = +6 (AP)
Next = 29+6 = 35
🧠 Trick: Differences equal → AP | Just add the common difference | 29+6=35
Q2HOT 100, 93, 86, 79, 72, ___?
Differences: −7, −7, −7, −7 → −7 (Decreasing AP)
Next = 72−7 = 65
🧠 Trick: Negative constant difference → Decreasing AP | 72−7=65
Q3HOT 2, 5, 8, ___, 14, 17
Pattern: +3 | 5−2=3, 8−5=3 | Missing = 8+3 = 11
🧠 Trick: AP में gap = common difference | 8+3=11 ✓ | 14−11=3 ✓
Q4HOT 3, 7, 6, 10, 9, ___, 12, 16
Odd positions: 3,6,9,12 (+3) | Even positions: 7,10,_,16 (+3) | Missing = 13
13
🧠 Trick: Alternating Series! Odd और Even positions अलग-अलग देखो | 7,10,13,16 (+3)
Q5HOT 1, 3, 6, 10, 15, 21, ___?
Differences: 2, 3, 4, 5, 6 → Increasing by 1
Next diff = 7 | 21+7 = 28
🧠 Trick: Increasing differences (1,2,3,4…) | These are Triangular Numbers | n(n+1)/2
✖️ Part 2: Geometric Series (गुणोत्तर श्रृंखला)
Q6HOT 3, 6, 12, 24, 48, ___?
Ratio: ×2 throughout
Next = 48×2 = 96
🧠 Trick: Each term ×2 = GP | 3→6→12→24→48→96
Q7HOT 5, 15, 45, 135, ___?
Ratio: ×3 | 5×3=15, 15×3=45, 45×3=135
135×3 = 405
🧠 Trick: ×3 GP | 135×3=405
Q8HOT 512, 256, 128, 64, ___?
Ratio: ÷2 (×½) throughout
64÷2 = 32
🧠 Trick: Each term halved | 64÷2=32 | Or: Powers of 2 → 2⁹,2⁸,2⁷,2⁶,2⁵=32
Q9HOT 2, 6, 18, ___, 162
×3 Pattern | 2×3=6, 6×3=18, 18×3=54
Missing = 54
🧠 Trick: ×3 GP | 18×3=54 ✓ | 54×3=162 ✓
🔲 Part 3: Squares & Cubes Series
🧠 Squares & Cubes याद करो
Squares: 1,4,9,16,25,36,49,64,81,100,121,144,169,196,225Cubes: 1,8,27,64,125,216,343,512,729,1000
Mixed: n²+1, n²−1, n²+n, n³+n etc.
Q10HOT 1, 4, 9, 16, 25, 36, ___?
Perfect Squares: 1²,2²,3²,4²,5²,6²
7² = 49
🧠 Trick: Perfect Squares Series | Next = 7²=49
Q11HOT 1, 8, 27, 64, 125, ___?
Perfect Cubes: 1³,2³,3³,4³,5³
6³ = 216
🧠 Trick: Perfect Cubes | 6³=216
Q12HOT 2, 5, 10, 17, 26, ___?
1²+1=2, 2²+1=5, 3²+1=10, 4²+1=17, 5²+1=26
6²+1 = 37
🧠 Trick: n²+1 Pattern | Differences: 3,5,7,9,11 (odd numbers) | 26+11=37
Q13HOT 3, 10, 29, 66, 127, ___?
1³+2=3, 2³+2=10, 3³+2=29, 4³+2=66, 5³+2=127
6³+2 = 216+2 = 218
🧠 Trick: n³+2 Pattern! | 1+2=3, 8+2=10, 27+2=29… | 216+2=218
Q14HOT 2, 9, 28, 65, 126, ___?
1³+1=2, 2³+1=9, 3³+1=28, 4³+1=65, 5³+1=126
6³+1 = 217
🧠 Trick: n³+1 Series | 6³+1=217
Q15HOT 0, 7, 26, 63, 124, ___?
1³−1=0, 2³−1=7, 3³−1=26, 4³−1=63, 5³−1=124
6³−1 = 215 → 215
🧠 Trick: n³−1 Series | 6³−1=215
Q16HOT 1, 5, 14, 30, 55, ___?
Differences: 4,9,16,25 = 2²,3²,4²,5²
Next diff = 6²=36 | 55+36 = 91
🧠 Trick: Differences = Perfect Squares! | 4,9,16,25,36 → add 36 | 55+36=91
🔁 Part 4: Fibonacci और Alternating Series
Q17HOT 1, 1, 2, 3, 5, 8, 13, ___?
Fibonacci: Each term = Sum of previous 2 | 8+13=21
21
🧠 Trick: Fibonacci = पिछले 2 का Sum | 8+13=21
Q18HOT 3, 4, 7, 11, 18, 29, ___?
Fibonacci type: 3+4=7, 4+7=11, 7+11=18, 11+18=29
18+29 = 47
🧠 Trick: Fibonacci Variant! Different starting numbers | 18+29=47
Q19HOT 1, 2, 3, 5, 8, 13, ___, 34
8+13=21 | 21
🧠 Trick: Fibonacci | 8+13=21 ✓ | 13+21=34 ✓
Q20HOT 2, 10, 4, 20, 6, 30, 8, ___?
Odd positions: 2,4,6,8 (+2) | Even positions: 10,20,30 (+10) | Next = Even → 40
🧠 Trick: Alternating Series! Odd: 2,4,6,8… Even: 10,20,30,40 | Next = 40
Q21HOT 3, 5, 7, 11, 11, 17, 15, ___?
Odd positions: 3,7,11,15 (+4) | Even positions: 5,11,17 (+6) | Next = Even → 17+6=23
🧠 Trick: Two Alternating APs! Odd: +4 | Even: +6 | 17+6=23
🔀 Part 5: Mixed / Complex Series
Q22HOT 1, 3, 7, 13, 21, 31, ___?
Differences: 2, 4, 6, 8, 10 → Even numbers increasing
Next diff = 12 | 31+12 = 43
🧠 Trick: Second level pattern! Diffs = 2,4,6,8,10,12 | 31+12=43
Q23HOT 4, 11, 25, 53, 109, ___?
4×2+3=11, 11×2+3=25, 25×2+3=53, 53×2+3=109
109×2+3 = 221
🧠 Trick: ×2+3 Pattern! | Each term = Previous×2+3 | 109×2+3=221
Q24HOT 2, 3, 6, 11, 18, 27, ___?
Differences: 1, 3, 5, 7, 9 → Odd numbers
Next diff = 11 | 27+11 = 38
🧠 Trick: Diffs = 1,3,5,7,9,11 (Odd Numbers) | 27+11=38
Q25HOT 5, 6, 9, 15, 26, 45, ___?
Differences: 1, 3, 6, 11, 19 | 2nd Diffs: 2, 3, 5, 8 → Fibonacci!
Next 2nd diff = 13 | Next 1st diff = 19+13=32 | 45+32 = 77
🧠 Trick: Differences की Differences देखो → Fibonacci pattern! | 45+32=77
Q26HOT 7, 14, 21, 35, 56, 91, ___?
7×2=14 | 7+14=21 | 14+21=35 | 21+35=56 | 35+56=91
56+91 = 147
🧠 Trick: Fibonacci Variant with ×7 start! Each = Sum of previous 2 | 56+91=147
Q27HOT 1, 2, 4, 8, 16, 32, ___, 128
Powers of 2: 2⁰,2¹,2²,2³,2⁴,2⁵,2⁶,2⁷
2⁶ = 64
🧠 Trick: Powers of 2 | ×2 each time | 32×2=64
❌ Part 6: Wrong Term (गलत पद) Series
🧠 Wrong Term Approach
Step 1: पूरी Series का Pattern निकालोStep 2: हर term check करो — कौन सा Pattern से match नहीं करता
Step 3: वह Wrong Term है → Correct Value निकालो
Q28HOT 1, 4, 9, 16, 25, 35, 49 — गलत पद?
Perfect Squares: 1,4,9,16,25,36,49 | 35 गलत है → 36 होना चाहिए
35 गलत है (36 होना चाहिए)
🧠 Trick: Perfect Squares 1²,2²,3²… | 6²=36 not 35 | Wrong=35
Q29HOT 2, 5, 10, 17, 26, 37, 50, 64 — गलत पद?
n²+1: 1+1=2✓, 4+1=5✓, 9+1=10✓, 16+1=17✓, 25+1=26✓, 36+1=37✓, 49+1=50✓, 64+1=65≠64
64 गलत है (65 होना चाहिए)
🧠 Trick: n²+1 Pattern | 8²+1=65 not 64 | Wrong=64
Q30HOT 3, 9, 27, 81, 243, 729, 2187, 6651 — गलत पद?
×3 GP | 3,9,27,81,243,729,2187,6561 | 6651≠6561
6651 गलत है (6561 होना चाहिए)
🧠 Trick: ×3 GP | 2187×3=6561 not 6651 | Wrong=6651
Q31HOT 6, 13, 25, 51, 101, 203 — गलत पद?
Pattern: ×2+1 | 6×2+1=13✓ | 13×2+1=27≠25 | Wrong!
25 गलत है (27 होना चाहिए)
🧠 Trick: ×2+1 | 13×2+1=27 not 25 | Wrong=25
Q32HOT 1, 5, 14, 30, 55, 91, 140 — गलत पद?
Differences: 4,9,16,25,36,49 = 2²,3²,4²,5²,6²,7² | 5+9=14✓ | 14+16=30✓ | 30+25=55✓ | 55+36=91✓ | 91+49=140✓ — सब सही!
सभी correct — कोई Wrong Term नहीं
🧠 Trick: Diffs = Perfect Squares sequence | Check each term carefully
Q33HOT 7, 12, 40, 222, 1765, 17660 — गलत पद?
7×1+5=12, 12×3+4=40, 40×5+2=202≠222 | 40×6=240≠222 | Try: n×(n+1)+something…
7×2−2=12, 12×3+4=40, 40×5+22=222, 222×7+119=1673≠1765 | Complex pattern
Try: ×1+5=12, ×2+16=40, ×5+22=222, ×7=1554≠1765 | Pattern analysis needed
🧠 Trick: Complex multiplier series | Multipliers: 1,2,5,7… check carefully
🔤 Part 7: Alphabet Series (वर्णमाला श्रृंखला)
🧠 Alphabet Series Master Tricks
हर Letter को Number में Convert करो (A=1,B=2…Z=26)EJOTY Trick: E=5, J=10, O=15, T=20, Y=25 → हर 5th letter
Pattern देखो: +2, +3, Skip letters, alternate letters etc.
Q34HOT A, C, E, G, I, ___?
A(1)→C(3)→E(5)→G(7)→I(9) | +2 each time (Alternate letters)
I(9)+2 = K(11) → K
🧠 Trick: Alternate letters (+2) | A,C,E,G,I,K | Odd-positioned letters
Q35HOT Z, X, V, T, R, ___?
Z(26)→X(24)→V(22)→T(20)→R(18) | −2 each time
R(18)−2 = P(16) → P
🧠 Trick: Reverse order Alternate letters | −2 each | 18−2=16=P
Q36HOT A, E, I, M, Q, ___?
A(1)→E(5)→I(9)→M(13)→Q(17) | +4 each time
Q(17)+4 = U(21) → U
🧠 Trick: +4 each | A=1,E=5,I=9,M=13,Q=17,U=21 | Vowels+some consonants
Q37HOT BDF, GIK, LNP, ___?
Each group: +2 spacing | BDF=2,4,6 | GIK=7,9,11 | LNP=12,14,16 | Next: 17,19,21=QSU
QSU
🧠 Trick: Groups में pattern: within group +2, between groups +1 gap | 17,19,21=QSU
Q38HOT AZ, BY, CX, DW, ___?
First letters: A,B,C,D (+1) | Second letters: Z,Y,X,W (−1)
Next: E(5) और V(22) → EV
🧠 Trick: First letter forward, Second letter backward | A+Z=27, B+Y=27, C+X=27… Opposite pairs!
Q39HOT ACE, BDF, CEG, DFH, ___?
First letter: A,B,C,D,E (+1) | Second: C,D,E,F,G (+1) | Third: E,F,G,H,I (+1)
Next: E,G,I → EGI
🧠 Trick: हर group में तीनों positions पर +1 | A,B,C,D,E | C,D,E,F,G | E,F,G,H,I
Q40HOT A, BB, CCC, DDDD, ___?
Letters: A,B,C,D,E | Count: 1,2,3,4,5
EEEEE
🧠 Trick: Letter = Next in sequence | Count = Position number | E × 5 = EEEEE
🔢 Part 8: Alpha-Numeric Series (मिश्रित श्रृंखला)
Q41HOT A1, B3, C5, D7, ___?
Letters: A,B,C,D,E (+1) | Numbers: 1,3,5,7,9 (+2, Odd)
E9
🧠 Trick: Letters +1, Numbers +2 | E=5th, 9=next odd | E9
Q42HOT 2A, 4C, 6E, 8G, ___?
Numbers: 2,4,6,8,10 (+2) | Letters: A,C,E,G,I (+2)
10I
🧠 Trick: Numbers +2 (Even), Letters +2 (Alternate) | 10,I=10I
Q43HOT Z1, X4, V9, T16, R25, ___?
Letters: Z,X,V,T,R,P (−2) | Numbers: 1,4,9,16,25,36 (Perfect Squares)
P36
🧠 Trick: Letters −2 each | Numbers = Perfect Squares | P(16th), 6²=36 | P36
Q44HOT A1B, C4D, E9F, G16H, ___?
Pattern: Consecutive letters | Middle number = Position² | 1²,2²,3²,4²,5²
I(9th letter), 5²=25, J(10th) → I25J
🧠 Trick: Letters sequential, Numbers = Squares | A-B=1, C-D=4, E-F=9, G-H=16, I-J=25
Q45HOT 3B, 6E, 9H, 12K, ___?
Numbers: 3,6,9,12,15 (+3) | Letters: B(2),E(5),H(8),K(11),N(14) (+3 positions)
15N
🧠 Trick: Number +3 | Letter position +3 | 15, N(14th letter) = 15N
🔀 Part 9: Number-Letter Mixed & Two-tier Series
Q46HOT 1, 4, 10, 22, 46, ___?
Pattern: ×2+2 | 1×2+2=4, 4×2+2=10, 10×2+2=22, 22×2+2=46
46×2+2 = 94
🧠 Trick: ×2+2 Pattern | Each term = Previous×2+2 | 94
Q47HOT 2, 3, 5, 9, 17, 33, ___?
Pattern: ×2−1 | 2×2−1=3, 3×2−1=5, 5×2−1=9, 9×2−1=17, 17×2−1=33
33×2−1 = 65
🧠 Trick: ×2−1 Series | 33×2−1=65
Q48HOT 3, 4, 6, 10, 18, 34, ___?
Differences: 1,2,4,8,16 → Powers of 2
Next diff = 32 | 34+32 = 66
🧠 Trick: Differences = 1,2,4,8,16,32… (Powers of 2) | 34+32=66
Q49HOT 1, 2, 6, 24, 120, ___?
Factorials: 1!=1, 2!=2, 3!=6, 4!=24, 5!=120
6! = 720
🧠 Trick: Factorial Series! 1!,2!,3!,4!,5!,6! | 6!=720
Q50HOT 0, 1, 1, 2, 4, 7, 13, 24, ___?
Each term = Sum of previous 3 | 0+1+1=2, 1+1+2=4, 1+2+4=7, 2+4+7=13, 4+7+13=24
7+13+24 = 44
🧠 Trick: Tribonacci Series (Sum of previous 3) | 7+13+24=44
🎯 Part 10: Railway Exam Special Q&A 2026-27
Q51HOT 4, 7, 11, 18, 29, 47, ___?
4+7=11, 7+11=18, 11+18=29, 18+29=47 | Fibonacci type
29+47 = 76
🧠 Trick: Each = Sum of previous 2 | 29+47=76
Q52HOT AB, DC, EF, HG, IJ, ___?
Odd groups: AB,EF,IJ (forward pairs) | Even groups: DC,HG (reverse pairs) | Pattern: pairs alternately normal and reversed | Next after IJ: LK (reverse)
LK
🧠 Trick: Alternate normal/reverse pairs | A-B(normal), D-C(reverse), E-F(normal), H-G(reverse), I-J(normal), L-K(reverse)
Q53HOT 2, 8, 18, 32, 50, ___?
2×1²=2, 2×2²=8, 2×3²=18, 2×4²=32, 2×5²=50
2×6² = 72 → 72
🧠 Trick: 2n² Pattern! n=1,2,3,4,5,6 | 2×36=72
Q54HOT 11, 13, 17, 19, 23, 29, 31, ___ (Next Prime)?
Prime Numbers Series: 11,13,17,19,23,29,31,37
37
🧠 Trick: Consecutive Primes | 31 के बाद 37 prime है (32,33,34,35,36 composite)
Q55HOT ABD, CEG, FHK, ___?
A(1)B(2)D(4): +1,+2 | C(3)E(5)G(7): +2,+2 | F(6)H(8)K(11): +2,+3 | Pattern changes
Next: I(9)L(12)P(16): +3,+4 → ILP
🧠 Trick: Each group’s internal gaps increase | +1,+2 → +2,+2 → +2,+3 → +3,+4
Q56HOT 125, 64, 27, 8, ___?
5³=125, 4³=64, 3³=27, 2³=8, 1³=?
1³ = 1
🧠 Trick: Decreasing Cubes 5³,4³,3³,2³,1³ | 1³=1
Q57HOT 100, 96.5, 89.5, 79, 65, ___?
Diffs: −3.5, −7, −10.5, −14 → Arithmetic with −3.5 each time
Next diff = −17.5 | 65−17.5 = 47.5
🧠 Trick: Increasing negative diffs (−3.5 more each time) | 65−17.5=47.5
Q58HOT 5, 11, 23, 47, 95, ___?
5×2+1=11, 11×2+1=23, 23×2+1=47, 47×2+1=95
95×2+1 = 191
🧠 Trick: ×2+1 Series | 95×2+1=191
Q59HOT ABZ, CDY, EFX, GHW, ___?
First two: AB,CD,EF,GH (consecutive pairs +2) | Third: Z,Y,X,W (−1 each)
Next: IJ, V → IJV
🧠 Trick: First pair: consecutive letters going forward | Third letter: going backward | IJ+V=IJV
Q60Expected 6, 11, 21, 36, 56, ___?
Differences: 5, 10, 15, 20 → Arithmetic with +5
Next diff = 25 | 56+25 = 81
🧠 Trick: Diffs = 5,10,15,20,25 (multiples of 5) | 56+25=81
⚡ Final Revision — Series Patterns Quick Reference
| Pattern | Identification | Example |
|---|---|---|
| AP (+d) | Equal differences | 3,7,11,15 (+4) |
| GP (×r) | Equal ratios | 2,6,18,54 (×3) |
| n² | Squares: 1,4,9,16… | 1,4,9,16,25 |
| n³ | Cubes: 1,8,27,64… | 1,8,27,64,125 |
| n²+k | Diffs=3,5,7,9 (odd) | 2,5,10,17(+1) |
| n³+k | Diffs=7,19,37,61 | 3,10,29,66(+2) |
| ×2+n | Each ×2+constant | 3,7,15,31(×2+1) |
| Fibonacci | Each=prev 2 sum | 1,1,2,3,5,8,13 |
| Alternating | 2 series mixed | 1,10,2,20,3,30 |
| Factorials | 1!,2!,3!… | 1,2,6,24,120 |
| Powers of 2 | 1,2,4,8,16… | Diffs also ×2 |
| Primes | 2,3,5,7,11… | No pattern formula |
| Wrong Term | One term breaks pattern | Find & fix it |
| Two-tier | 2nd diff = AP/GP | 1,2,4,7,11,16 |
📌 Railway Group D 2026-27 Series के Most Expected:
AP (+d constant) · GP (×r constant) · n² Series · n³±k Series · ×2+1/×2−1 Pattern · Fibonacci (prev 2 sum) · Alternating (2 series mix) · Wrong Term identification · Increasing differences · Powers of 2 (diffs also ×2) · Alpha-numeric combinations
AP (+d constant) · GP (×r constant) · n² Series · n³±k Series · ×2+1/×2−1 Pattern · Fibonacci (prev 2 sum) · Alternating (2 series mix) · Wrong Term identification · Increasing differences · Powers of 2 (diffs also ×2) · Alpha-numeric combinations
🔗 Related Study Material
🔤 Railway Coding-Decoding Marathon 2027 HOT 🔢 Railway Number System Marathon 2027 › 📊 Railway Maths Complete Q&A 2027 › 📝 Free Mock Test Series 2026 ›📈 Railway RRB Group D Number & Alphabet Series Marathon Complete — Railway Exam जीतो!
Daily Study Material + Free Mock Tests + Latest Vacancies — MahilaBharti.in पर।
🏠 Home Page 📝 Free Mock Test