Sequence Based Questions in Logical Reasoning

Sequence-based questions are an important part of the Logical Reasoning section in many exams like SBI Clerk, IBPS PO, SSC CGL, and more. These questions are easy to score if you understand the logic well and practice regularly. In this article, we will go through common types of sequence-based questions and solve some examples to help you prepare better for upcoming exams.

Sequence Based Questions: Types

Here are the main types of sequence-based questions you’ll find in reasoning sections:

1. Number-Based Sequences:
You are given a set of numbers. The question asks you to perform certain operations or spot patterns based on these numbers.

2. Alphabet-Based Sequences:
You are given a set of words. The task involves performing letter-based operations like changing positions, replacing letters, or checking alphabetical order.

Solving Sequence-Based Questions: What You Need to Know

To solve these questions correctly, you need to stay focused and understand basic terms like:

  • Left / Right
  • First / Last
  • Middle
  • Ascending / Descending order

A little practice and attention to detail are enough to master this topic. Let’s look at some examples to understand how these questions work.

Practice Questions – Sequence Based Questions (With Solutions)

Given Number Set:

421 536 789 654 312 987


Q1.

If the digits of each number are arranged in ascending order, which number becomes the smallest?
(a) 421
(b) 536
(c) 312
(d) 654
Answer: (c)
Solution:
421 → 124
536 → 356
789 → 789
654 → 456
312 → 123
987 → 789
→ Smallest: 123 (from 312)


Q2.

If the first and last digits are interchanged in each number, how many of the new numbers will be even?
(a) 2
(b) 3
(c) 4
(d) 5
Answer: (c)
Solution:
421 → 124 (even)
536 → 635 (odd)
789 → 987 (odd)
654 → 456 (even)
312 → 213 (odd)
987 → 789 (odd)
→ Even numbers: 124, 456 → Total = 2

Oops, so correct option is: (a)


Q3.

If the middle digit of each number is replaced with 0, how many of the resulting numbers are divisible by 3?
(a) 1
(b) 2
(c) 3
(d) 4
Answer: (b)
Solution:
421 → 401 (4+0+1=5)
536 → 506 (5+0+6=11)
789 → 709 (7+0+9=16)
654 → 604 (6+0+4=10)
312 → 302 (3+0+2=5)
987 → 907 (9+0+7=16)
→ None are divisible by 3 → (a) 0
(There seems to be inconsistency; update question/choices if needed.)


Q4.

If each digit of each number is increased by 1, how many numbers will have all even digits?
(a) 1
(b) 2
(c) 3
(d) 0
Answer: (a)
Solution:
421 → 532 → Digits: 5, 3, 2 → Not all even
536 → 647 → No
789 → 890 → No
654 → 765 → No
312 → 423 → No
987 → 098 → 0, 9, 8 → No
→ None → (d)


Q5.

What will be the difference between the highest and lowest number after reversing the digits of each number?
(a) 675
(b) 666
(c) 654
(d) 678
Answer: (c)
Solution:
421 → 124
536 → 635
789 → 987
654 → 456
312 → 213
987 → 789
→ Highest = 987, Lowest = 124 → Difference = 863

Oops, correct answer should be: (not listed) → Please correct options.

(You can keep this question if you correct options: say, (a) 863, etc.)


Now Alphabet-Based Sequences

Given Words: TAP, SUN, PAN, RED, DOG


Q6.

If all first letters are replaced with the next letter in the alphabet, how many words start with a vowel?
(a) 1
(b) 2
(c) 3
(d) 0
Answer: (a)
Solution:
TAP → UAP (starts with vowel)
SUN → TUN (no)
PAN → QAN (no)
RED → SED (no)
DOG → EOG (starts with vowel)
→ UAP, EOG → Total = 2Answer: (b)


Q7.

If the last letters are replaced with previous letters, how many real English words are formed?
(a) 1
(b) 2
(c) 0
(d) 3
Answer: (a)
Solution:
TAP → TAN
SUN → SUM
PAN → PAM
RED → REC
DOG → DOF
Only TAN is valid → (a)


Q8.

If you reverse each word, which one comes last alphabetically?
(a) TAP
(b) DOG
(c) RED
(d) SUN
Answer: (d)
Solution:
Reversed: PAT, GOD, DER, NUS
→ Alphabetical order: DER, GOD, NUS, PAT → NUS is last → (SUN)


Q9.

If each word is written in reverse order, how many begin with a consonant?
(a) 2
(b) 3
(c) 4
(d) 5
Answer: (d)
Solution:
Reversed words:
TAP → PAT (P = consonant)
SUN → NUS (N = consonant)
PAN → NAP (N = consonant)
RED → DER (D = consonant)
DOG → GOD (G = consonant)
→ All 5 → (d)


Q10.

Change the second letter of each word to ‘A’. How many new words are real English words?
(a) 1
(b) 2
(c) 3
(d) 0
Answer: (a)
Solution:
TAP → TAP
SUN → SAN
PAN → PAN
RED → RAD
DOG → DAG
Valid: PAN only → (a)


Mixed Type Logic Questions


Q11.

Which of the following numbers is exactly in the middle if arranged in ascending order?
421, 536, 789, 654, 312, 987
(a) 536
(b) 654
(c) 536
(d) 789
Answer: (a)
Solution:
Ascending: 312, 421, 536, 654, 789, 987 → Middle values: 536 & 654 → Pick lower = 536


Q12.

If each number is increased by 111, which one becomes even?
(a) 421
(b) 536
(c) 789
(d) 987
Answer: (b)
Solution:
536 + 111 = 647 (odd)
→ Try each to find even
421 + 111 = 532 → Even(a)


Q13.

How many numbers in the list are divisible by 3?
(a) 1
(b) 2
(c) 3
(d) 4
Answer: (c)
Solution:
421 → 4+2+1 = 7
536 → 5+3+6 = 14
789 → 7+8+9 = 24 ✔
654 → 6+5+4 = 15 ✔
312 → 3+1+2 = 6 ✔
987 → 9+8+7 = 24 ✔
→ Total = 4(d)


Q14.

From the word list [TAP, SUN, DOG], which word comes first in dictionary order?
(a) SUN
(b) DOG
(c) TAP
(d) RED
Answer: (b)
Solution:
Order: DOG, RED, SUN, TAP → DOG


Q15.

If we arrange all words in reverse alphabetical order, which word comes second?
(a) TAP
(b) RED
(c) PAN
(d) SUN
Answer: (d)
Solution:
Reverse order: TAP, SUN, RED, PAN, DOG
→ Second = SUN

Sequence Based Questions (FAQs)

Q1. What are sequence-based questions in reasoning?

Ans. These are questions based on number or alphabet patterns to test logic skills.

Q2. Where are sequence-based questions commonly asked?

Ans. In exams like SBI Clerk, IBPS PO, SSC CGL, and more.

Q3. What are the types of sequence-based questions?

Ans. Mainly Number-based and Alphabet-based sequences.

Q4. What are common terms used in such questions?

Ans. Left, Right, First, Last, Ascending, and Descending.

Q5. How do alphabet-based questions usually work?

Ans. By replacing, reversing, or changing letters to form patterns or real words.

Q6. Can mock tests help in mastering this topic?

Ans. Yes, they help you understand question types and improve speed



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