A square-number list was entered as 144, 169, 196, 226, 256, 289. Identify the typing error.

The terms are 12² through 17². Since 15² = 225, the printed term 226 is wrong.

A sequence begins 20, 33, 42, 47. Its successive gaps decrease by 4 throughout. What is the largest term among its first 10 terms?

The gaps are 13, 9, 5, 1, −3, −7, ... . The sequence peaks at 47 + 1 = 48 and then decreases.

Which value extends 720, 360, 1080, 270, 1350, 225, ? using the continuing operation pattern?

The operations are ÷2, ×3, ÷4, ×5, ÷6, then ×7. Thus 225 × 7 = 1575.

The bases of 27, 125, 343, 1331, 2197, ? form a special number sequence. Find the next cube.

The cube bases are consecutive primes 3, 5, 7, 11, 13, then 17. Hence 17³ = 4913.

Each term after the first two is their running sum. Recover the first two terms, in order, of ?, ?, 17, 28, 45, 73.

The second term is 28 − 17 = 11. The first term is 17 − 11 = 6, giving the pair (6, 11).

Complete the alternating calculation chain 4, 11, 35, 73, 221, ?.

Alternate ×2 + 3 and ×3 + 2. The required step is 221 × 2 + 3 = 445.

In 2, 121, 6, 100, 24, 81, 120, 64, 720, ?, which number completes the even-position strand?

Odd positions contain 2!, 3!, 4!, 5!, 6!. Even positions are 11², 10², 9², 8², then 7² = 49.

Examine 12, 18, 33, 68, 145, 288, ? . Its gaps are products of adjacent primes. Determine the next term.

The gaps are 2×3, 3×5, 5×7, 7×11, 11×13. Next add 13 × 17 = 221, giving 288 + 221 = 509.

An 8-term arithmetic series starts at 17 and ends at 80. What is the sum of its 4th and 5th terms?

In an arithmetic series, equally distant pairs from the ends have the same sum. Thus the 4th and 5th terms add to 17 + 80 = 97.

Only one entry is wrong in 4, 7, 9, 20, 36, 66, 121, 222. Locate it using a three-term recurrence.

Each term should equal the sum of the previous three. The sixth term is 9 + 20 + 36 = 65, and then 20 + 36 + 65 = 121 and 36 + 65 + 121 = 222; hence 66 is wrong.

In a geometric series with a positive common ratio, the 2nd term is 54 and the 5th is 1458. What is the 3rd term?

Three ratio steps give 1458 ÷ 54 = 27 = 3³, so the common ratio is 3. The 3rd term is 54 × 3 = 162.

What replaces the final blank in 12, 17, 45, 220, 1536, ? when prime multipliers and descending subtractions operate together?

The operations are ×2 − 7, ×3 − 6, ×5 − 5, ×7 − 4. Next is ×11 − 3, giving 1536 × 11 − 3 = 16893.

The recurrence in 2, 6, 9, 14, 24, 37, ? includes alternating adjustments. Select the next term.

Add the previous two terms, then alternate +1 and −1. The next adjustment is +1, so 24 + 37 + 1 = 62.

The entries 19, 37, 61, 91, 127, ? equal differences of consecutive cubes. Find the missing entry.

The terms run from 3³ − 2³ through 7³ − 6³. Next is 8³ − 7³ = 512 − 343 = 169.

In 47, 51, 42, 67, 18, 139, ?, the jumps combine primes, powers and alternating signs. Which number is next?

-30. The differences are +2², −3², +5², −7², +11². The next is −13² = −169, so 139 − 169 = −30.

Two strands share the same changing factors in opposite ways: 3, 5040, 6, 2520, 18, 840, 72, 210, 360, 42, ?, ? . Choose the next pair.

Odd positions multiply by 2, 3, 4, 5, then 6; even positions divide by the same factors. Thus the next pair is (360 × 6, 42 ÷ 6) = (2160, 7).

A processor repeatedly squares its current value and subtracts 2. Its outputs are 3, 7, ?, 2207. Recover the missing output.

The missing value is 7² − 2 = 47. It checks because 47² − 2 = 2207.

Adding each term’s digit sum should generate the next term in 26, 34, 41, 46, 57, 67. Which entry violates this rule?

46 + 4 + 6 = 56, not 57. With that correction, 56 + 5 + 6 = 67, so only 57 is wrong.

Pair primes with exactly one prime between them: 3 + 7, 5 + 11, 7 + 13, and so on. Their sums form 10, 16, 20, 28, 32, 40, ? . Find the next sum.

The last given sum is 17 + 23 = 40. The next pair is 19 and 29, with only 23 between them, so 19 + 29 = 48.

Which continuation fits 100, 102, 105, 109, 118, 126, 153, ? after splitting the gaps into two alternating lists?

The gaps are 2, 3, 4, 9, 8, 27. Alternate gap lists are 2, 4, 8, 16 and 3, 9, 27, so add 16: 153 + 16 = 169.

A four-term moving window drives 1, 4, 6, 9, 18, 29, 50, 88, ? . Determine the next term.

Add the latest three terms and subtract the term immediately before them: 29 + 50 + 88 − 18 = 149. This also gives 18 + 29 + 50 − 9 = 88.

A multiplication pattern repeats each multiplier twice: 5, 10, 20, 60, 180, 720, ? . Select the next number.

The multipliers are 2, 2, 3, 3, 4, 4. Hence 720 × 4 = 2880.

Puneet adds each number to the number formed by reversing its digits: 24, 66, 132, 363, 726, 1353, ? . What is next?

Reversing 1353 gives 3531. Therefore 1353 + 3531 = 4884.

Complete the second strand in 22, 6, 26, 10, 34, 15, 38, 21, 46, ?.

Odd positions are twice the consecutive primes 11, 13, 17, 19, 23. Even positions are triangular numbers 6, 10, 15, 21, 28, so the answer is 28.

The series 50, 54, 62, 71, 98, 114, 178, ?, ? uses square and cube jumps in pairs. Which ordered pair completes it?

(203, 328). The gaps are 2², 2³, 3², 3³, 4², 4³, then 5², 5³. Thus 178 + 25 = 203 and 203 + 125 = 328.

Topic

Number Series MCQ – Part 4 - Topic Guide and MCQs

Part of Reasoning > 01 Number Series - 25 questions, about 25 min, with an explanation after every answer.

Question count

about 25 min

Estimated time

Mixed

Difficulty

02 Nov 2026

Last updated

Quick answer

Number Series MCQ – Part 4 is a topic inside Reasoning (01 Number Series). It runs 25 untimed MCQs - roughly 25 min - and the review explains every answer once you submit.

Topic introduction

What Number Series MCQ – Part 4 covers

The shape of the set before you start it.

Number Series MCQ – Part 4 sits inside Reasoning, under the 01 Number Series lane, and the portal keeps it as one self-contained set: 25 questions, four options each, no clock and a written explanation behind every answer.

Attempt it once to find the gaps, read why each distractor is wrong, then retake the same set a few days later. The questions you miss twice are the ones worth writing down.

Curated by Gurpreet Singh · Punjab Police SI, Rank 2 (713/800) · Founder, House of Aspirants · Read his story →

Question bank

Number Series MCQ – Part 4: all 25 questions

Read the question, pick an option, then open the answer.

A square-number list was entered as 144, 169, 196, 226, 256, 289. Identify the typing error.
1. 256
2. 196
3. 226
4. 289
Show answer

Answer: (C) 226

Explanation: The terms are 12² through 17². Since 15² = 225, the printed term 226 is wrong.
A sequence begins 20, 33, 42, 47. Its successive gaps decrease by 4 throughout. What is the largest term among its first 10 terms?
1. 47
2. 48
3. 52
4. 49
Show answer

Answer: (B) 48

Explanation: The gaps are 13, 9, 5, 1, −3, −7, ... . The sequence peaks at 47 + 1 = 48 and then decreases.
Which value extends 720, 360, 1080, 270, 1350, 225, ? using the continuing operation pattern?
1. 1350
2. 1125
3. 1925
4. 1575
Show answer

Answer: (D) 1575

Explanation: The operations are ÷2, ×3, ÷4, ×5, ÷6, then ×7. Thus 225 × 7 = 1575.
The bases of 27, 125, 343, 1331, 2197, ? form a special number sequence. Find the next cube.
1. 4913
2. 4096
3. 6859
4. 3375
Show answer

Answer: (A) 4913

Explanation: The cube bases are consecutive primes 3, 5, 7, 11, 13, then 17. Hence 17³ = 4913.
Each term after the first two is their running sum. Recover the first two terms, in order, of ?, ?, 17, 28, 45, 73.
1. (11, 6)
2. (6, 11)
3. (5, 12)
4. (7, 10)
Show answer

Answer: (B) (6, 11)

Explanation: The second term is 28 − 17 = 11. The first term is 17 − 11 = 6, giving the pair (6, 11).
Complete the alternating calculation chain 4, 11, 35, 73, 221, ?.
1. 444
2. 445
3. 443
4. 665
Show answer

Answer: (B) 445

Explanation: Alternate ×2 + 3 and ×3 + 2. The required step is 221 × 2 + 3 = 445.
In 2, 121, 6, 100, 24, 81, 120, 64, 720, ?, which number completes the even-position strand?
1. 36
2. 5040
3. 49
4. 25
Show answer

Answer: (C) 49

Explanation: Odd positions contain 2!, 3!, 4!, 5!, 6!. Even positions are 11², 10², 9², 8², then 7² = 49.
Examine 12, 18, 33, 68, 145, 288, ? . Its gaps are products of adjacent primes. Determine the next term.
1. 457
2. 431
3. 535
4. 509
Show answer

Answer: (D) 509

Explanation: The gaps are 2×3, 3×5, 5×7, 7×11, 11×13. Next add 13 × 17 = 221, giving 288 + 221 = 509.
An 8-term arithmetic series starts at 17 and ends at 80. What is the sum of its 4th and 5th terms?
1. 97
2. 80
3. 63
4. 194
Show answer

Answer: (A) 97

Explanation: In an arithmetic series, equally distant pairs from the ends have the same sum. Thus the 4th and 5th terms add to 17 + 80 = 97.
Only one entry is wrong in 4, 7, 9, 20, 36, 66, 121, 222. Locate it using a three-term recurrence.
1. 222
2. 121
3. 36
4. 66
Show answer

Answer: (D) 66

Explanation: Each term should equal the sum of the previous three. The sixth term is 9 + 20 + 36 = 65, and then 20 + 36 + 65 = 121 and 36 + 65 + 121 = 222; hence 66 is wrong.
In a geometric series with a positive common ratio, the 2nd term is 54 and the 5th is 1458. What is the 3rd term?
1. 216
2. 486
3. 108
4. 162
Show answer

Answer: (D) 162

Explanation: Three ratio steps give 1458 ÷ 54 = 27 = 3³, so the common ratio is 3. The 3rd term is 54 × 3 = 162.
What replaces the final blank in 12, 17, 45, 220, 1536, ? when prime multipliers and descending subtractions operate together?
1. 16896
2. 10749
3. 16893
4. 16889
Show answer

Answer: (C) 16893

Explanation: The operations are ×2 − 7, ×3 − 6, ×5 − 5, ×7 − 4. Next is ×11 − 3, giving 1536 × 11 − 3 = 16893.
The recurrence in 2, 6, 9, 14, 24, 37, ? includes alternating adjustments. Select the next term.
1. 62
2. 61
3. 60
4. 63
Show answer

Answer: (A) 62

Explanation: Add the previous two terms, then alternate +1 and −1. The next adjustment is +1, so 24 + 37 + 1 = 62.
The entries 19, 37, 61, 91, 127, ? equal differences of consecutive cubes. Find the missing entry.
1. 169
2. 168
3. 171
4. 153
Show answer

Answer: (A) 169

Explanation: The terms run from 3³ − 2³ through 7³ − 6³. Next is 8³ − 7³ = 512 − 343 = 169.
In 47, 51, 42, 67, 18, 139, ?, the jumps combine primes, powers and alternating signs. Which number is next?
1. -4
2. -30
3. -42
4. 308
Show answer

Answer: (B) -30

Explanation: The differences are +2², −3², +5², −7², +11². The next is −13² = −169, so 139 − 169 = −30.
Two strands share the same changing factors in opposite ways: 3, 5040, 6, 2520, 18, 840, 72, 210, 360, 42, ?, ? . Choose the next pair.
1. (2160, 7)
2. (1800, 7)
3. (2160, 6)
4. (2520, 7)
Show answer

Answer: (A) (2160, 7)

Explanation: Odd positions multiply by 2, 3, 4, 5, then 6; even positions divide by the same factors. Thus the next pair is (360 × 6, 42 ÷ 6) = (2160, 7).
A processor repeatedly squares its current value and subtracts 2. Its outputs are 3, 7, ?, 2207. Recover the missing output.
1. 51
2. 49
3. 47
4. 45
Show answer

Answer: (C) 47

Explanation: The missing value is 7² − 2 = 47. It checks because 47² − 2 = 2207.
Adding each term’s digit sum should generate the next term in 26, 34, 41, 46, 57, 67. Which entry violates this rule?
1. 67
2. 57
3. 41
4. 46
Show answer

Answer: (B) 57

Explanation: 46 + 4 + 6 = 56, not 57. With that correction, 56 + 5 + 6 = 67, so only 57 is wrong.
Pair primes with exactly one prime between them: 3 + 7, 5 + 11, 7 + 13, and so on. Their sums form 10, 16, 20, 28, 32, 40, ? . Find the next sum.
1. 44
2. 52
3. 46
4. 48
Show answer

Answer: (D) 48

Explanation: The last given sum is 17 + 23 = 40. The next pair is 19 and 29, with only 23 between them, so 19 + 29 = 48.
Which continuation fits 100, 102, 105, 109, 118, 126, 153, ? after splitting the gaps into two alternating lists?
1. 177
2. 185
3. 180
4. 169
Show answer

Answer: (D) 169

Explanation: The gaps are 2, 3, 4, 9, 8, 27. Alternate gap lists are 2, 4, 8, 16 and 3, 9, 27, so add 16: 153 + 16 = 169.
A four-term moving window drives 1, 4, 6, 9, 18, 29, 50, 88, ? . Determine the next term.
1. 167
2. 159
3. 149
4. 138
Show answer

Answer: (C) 149

Explanation: Add the latest three terms and subtract the term immediately before them: 29 + 50 + 88 − 18 = 149. This also gives 18 + 29 + 50 − 9 = 88.
A multiplication pattern repeats each multiplier twice: 5, 10, 20, 60, 180, 720, ? . Select the next number.
1. 1440
2. 3600
3. 2160
4. 2880
Show answer

Answer: (D) 2880

Explanation: The multipliers are 2, 2, 3, 3, 4, 4. Hence 720 × 4 = 2880.
Puneet adds each number to the number formed by reversing its digits: 24, 66, 132, 363, 726, 1353, ? . What is next?
1. 4888
2. 3531
3. 4884
4. 2706
Show answer

Answer: (C) 4884

Explanation: Reversing 1353 gives 3531. Therefore 1353 + 3531 = 4884.
Complete the second strand in 22, 6, 26, 10, 34, 15, 38, 21, 46, ?.
1. 28
2. 27
3. 25
4. 29
Show answer

Answer: (A) 28

Explanation: Odd positions are twice the consecutive primes 11, 13, 17, 19, 23. Even positions are triangular numbers 6, 10, 15, 21, 28, so the answer is 28.
The series 50, 54, 62, 71, 98, 114, 178, ?, ? uses square and cube jumps in pairs. Which ordered pair completes it?
1. (242, 367)
2. (203, 328)
3. (203, 303)
4. (194, 319)
Show answer

Answer: (B) (203, 328)

Explanation: The gaps are 2², 2³, 3², 3³, 4², 4³, then 5², 5³. Thus 178 + 25 = 203 and 203 + 125 = 328.

Why it matters

Why Number Series MCQ – Part 4 is worth the hours

Where the marks actually come from.

Number Series MCQ – Part 4 is factual rather than analytical: you either recall it in seconds or you lose the mark to somebody who did. That makes it one of the cheapest sections to convert - a handful of short sittings usually settles the whole cluster.

Exam relevance

Exams where Number Series MCQ – Part 4 matters

Derived from the subject and lane this topic belongs to.

Punjab Police Constable

The highest-volume recruitment on this list. Build your base with Punjab GK and current affairs, then drill reasoning until speed is automatic.

Punjab Police ASI

Assistant Sub-Inspector papers separate candidates on English and Punjabi accuracy as much as on general awareness. Practise language daily.

Punjab Police Sub-Inspector (SI)

The most competitive paper here. Polity, history and quant reasoning decide the rank - so take full timed mocks before the exam.

Punjab Police Jail Warder

A tighter syllabus: general awareness, Punjabi and basic reasoning. Perfect for a daily quiz habit - short sessions, high consistency.

Punjab Police Driver

A driving post inside Punjab Police. Keep general awareness and reasoning moving with short daily sets here while you work on the driving side separately.

Punjab Police Wireless Operator

A technical post inside Punjab Police. Alongside your wireless study, general awareness and reasoning are the parts you can drill here every day as MCQs.

Punjab Police IT Cadre

A technology-focused cadre inside Punjab Police. Computer awareness and reasoning are the highest-yield blocks to practise here as short daily MCQ sets.

Patwari

Revenue work starts with Punjab geography, history and current affairs. Add quant for the sections that reward calculation speed.

Excise Inspector

General awareness and English carry this paper. Track Punjab policy news daily and revise it as MCQs, not as notes.

Clerk

Grammar, comprehension, typing and basic computer knowledge. Accuracy beats speed here - review every wrong answer.

Lab Attendant

A short, high-scoring paper: lab safety, general science and reasoning. Ten focused minutes a day is usually enough to cover it.

PSPCL jobs

Recruitment by the Punjab State Power Corporation Limited. Technical aptitude sits alongside general awareness and reasoning.

PSSSB

PSSSB recruitment. Whichever post you are writing, general awareness, Punjabi and reasoning are the shared subjects you can practise here as daily MCQs.

Punjab Police Head Constable

The communication and clerical tier of Punjab Police. Punjabi, English and general knowledge carry the paper, and computer awareness is worth real marks.

Staff Selection Commission

The central recruitment ladder most aspirants attempt alongside a state paper. Arithmetic, reasoning and English decide the score; general awareness decides the cutoff.

Railway Recruitment

A high-volume, high-speed paper. Arithmetic, reasoning and general awareness asked at a pace that punishes anyone still working out method during the attempt.

Banking Exams

Quantitative aptitude and reasoning at speed, with a separate English section and a general awareness paper that moves with the financial news cycle.

Expected questions

Expected questions from Number Series MCQ – Part 4

What an examiner usually reaches for in this cluster.

Expect one-line recall questions - definitions, stand-for expansions, identifiers and the ordering of things. Practise the wording as well as the concept: these papers test terminology, and the set above uses the same four-option shape they do.

Daily habit

Keep the Expected MCQs habit running

20 fresh mixed questions a day, plus the current-affairs sets examiners keep reusing.

Daily Quiz Expected MCQs

Previous year questions

Previous Year Questions

How this topic behaves in real papers.

Past papers reuse clusters like this almost verbatim across years and posts. Run the same set until every distractor is familiar - previous-year style questions stop being recall and start being free marks.

Where the previous-year sets live

The portal's previous-year practice runs through the General Knowledge lane and the daily mixed quiz.

Previous Year Questions Daily Quiz

Keep going

Take the Number Series MCQ – Part 4 quiz

25 questions, about 25 min, instant scoring and a full review at the end.

Start Number Series MCQ – Part 4 quiz Reasoning page Daily Quiz Mock Tests

Questions

Number Series MCQ – Part 4 - common questions

Answered against the set as it is published today.

All questions →

How long is the Number Series MCQ – Part 4 quiz?

Number Series MCQ – Part 4 runs 25 untimed questions - about 25 min at a steady pace. The set clears at 40% and you can retake it as often as you like.

What kind of questions does Number Series MCQ – Part 4 ask?

The set answers that: each question carries four options and a full explanation, so you learn the wording an examiner uses, not just the fact behind it.

Where else can I practise Reasoning?

Open the quiz page above, or start from the Reasoning subject page if you want to drill neighbouring lanes in the same sitting.

Do my scores save?

Scores, bookmarks and streaks need the optional Google sign-in. Opening the set and answering questions does not.