Preparing for the RRB NTPC exam? You’re aware that the competition for Railway jobs is extremely high. If you want to crack this exam than you should value every single mark. In the General Intelligence and Reasoning section, there is one topic that appears the most: Series Completion. You have seen these questions before. A string of numbers like 2, 5, 10, 17, ? or letters like AZ, BY, CX, ?. They look like simple puzzles. But still, most candidates fail due to less practice. These questions can waste your precious time if you don’t spot the pattern quickly. In the exam hall pressure, your brain might get stuck finding the logic. To help you with these issues we have provided exam-level, frequently asked series questions for RRB NTPC.
Why are Series Questions Important?
In RRB NTPC, the Reasoning section is the highest-scoring area.
- High Weightage: You can expect 3 to 5 questions from the Number and Alphabet Series combined. That’s solid marks in your pocket.
- Brain Warm-up: Solving these questions first gives you confidence for the tougher Math section.
- Simple Logic: Unlike Bank exams, Railway series questions are direct. You don’t need complex multi-step calculations.
Common Types of Series You Must Know
Before you start practicing, you should know what to look for.
- Number Series: Based on addition, subtraction, multiplication, squares, or cubes.
- Alphabet Series: Based on the position of letters (A=1, B=2…).
- Continuous Pattern Series: Jumbled letters like a_b_c_a_.
Download Free PDF of Series Questions for RRB NTPC
We have analyzed many years of previous question papers to provide you with the most important questions that can boost your preparation. These questions match the exact difficulty level of the exam. Download this PDF, save it, and practice these questions daily to improve your speed.
Q1. Find the missing number:
6, 12, 21, 33, ?
(a) 45
(b) 48
(c) 40
(d) 46
Answer: (b) 48
Logic: Differences: 6, 9, 12 → increasing by 3. Next difference = 15.
33 + 15 = 48
Q2. Complete the series:
1, 8, 27, 64, ?
(a) 100
(b) 125
(c) 121
(d) 81
Answer: (b) 125
Logic: Perfect cubes: 1³, 2³, 3³, 4³ → next is 5³ = 125
Q3. Select the missing term:
B, E, H, K, ?
(a) M
(b) N
(c) O
(d) L
Answer: (b) N
Logic: Alphabet gap of +3: B → E → H → K → N
Q4. Find the wrong number in the series:
3, 7, 15, 27, 63, 127
(a) 27
(b) 63
(c) 15
(d) 7
Answer: (a) 27
Logic: Pattern is ×2 + 1.
15 × 2 + 1 = 31, but 27 is given.
Q5. Find the next number:
2, 3, 5, 7, 11, ?
(a) 12
(b) 13
(c) 14
(d) 15
Answer: (b) 13
Logic: Consecutive prime numbers.
Q6. Complete the letter series:
AZ, CX, EV, GT, ?
(a) HS
(b) IR
(c) JQ
(d) KP
Answer: (b) IR
Logic:
First letters: A, C, E, G (+2) → I
Second letters: Z, X, V, T (−2) → R
Q7. Find the next number:
10, 18, 28, 40, 54, ?
(a) 70
(b) 72
(c) 68
(d) 74
Answer: (a) 70
Logic: Differences: 8, 10, 12, 14 → next is 16
54 + 16 = 70
Q8. Find the missing number:
120, 99, 80, 63, 48, ?
(a) 35
(b) 38
(c) 39
(d) 40
Answer: (a) 35
Logic: n² − 1:
11²−1, 10²−1, 9²−1, 8²−1, 7²−1 → next is 6²−1 = 35
Q9. Find the missing letters:
a _ b c c _ a _ b b _ c
(a) a, b, a, c
(b) a, c, c, a
(c) b, a, a, c
(d) b, a, b, a
Answer: (a) a, b, a, c
Logic: Repeating pattern: aabbcc / aabbcc
Q10. Find the next number:
5, 11, 24, 51, 106, ?
(a) 215
(b) 217
(c) 220
(d) 210
Answer: (b) 217
Logic: ×2 + 1, ×2 + 2, ×2 + 3, ×2 + 4, ×2 + 5
106 × 2 + 5 = 217
How to Prepare Series Questions Easily?
Solving Series is not magic; it is a method. Most candidates don’t know these methods, due to which they fail to solve these questions easily. Below, we have mentioned some tips and tricks that will help you solve these questions easily.
- Learn Squares & Cubes: This is the most important tip. Memorize squares up to 30 and cubes up to 15. If you see “343,” your brain should instantly scream “7 cubed!”
- The Difference Method: If you are stuck on a number series, find the difference between the numbers. 90% of the time, the logic is hidden in the difference (or the difference of the difference).
- Write the Alphabet: In the exam, write A to Z with their numbers (1-26) on your rough sheet immediately. It helps immensely with letter series.
- Don’t Spend Too Much Time: Series questions can be traps. If you don’t see the logic in 30-40 seconds, skip it and come back later.
- Practice Topic Tests: You need muscle memory for this. Attempt our Free Topic Tests to train your brain to spot patterns faster.
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FAQs: Series Questions for RRB NTPC
No. It ranges from Easy to Moderate. The patterns are usually standard (squares, cubes, addition).
You can expect around 3 to 5 questions in the General Intelligence and Reasoning section.
Check the gap (difference) between numbers first. If the gap increases slowly, it is an addition. If it increases very fast, it is multiplication.
You can download the free, exam-level PDF by clicking the link provided in the middle of this blog post.
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