Quantitative Aptitude

Number Series

2,662 Questions
All First differences and arithmetic progressions 812 Successive multiplication or division 429 Step-wise calculations 349 Squares and cubes based 338 Separate alternate positions 241 Inter-term operations 144 Mixed-operation rules 138 Unconventional pattern solving 74 Fractional and decimal operations 60 Prime number based 54 Digit operations 23

Number Series Questions

Multiple choice

In each of these questions a number series is given. In each series, only one number is wrong. Find out the wrong number. 648, 80, 740, 87, 760, 94

  1. 740

  2. 760

  3. 648

  4. 87

  5. 94
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is an alternating series. The second series (80, 87, 94) increases by 7 each time consistently. The first series should follow a pattern but 740 breaks it. If we examine 648, 740, 760 - the jumps are +92 and +20, which is inconsistent. 740 is likely the wrong number that disrupts the pattern.

Multiple choice

A series is given with a pattern than choose the correct alternative from the given ones that will complete the series. 436, 382, 337, 238, _____

  1. 167

  2. 159

  3. 138

  4. 148
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The pattern is that each number equals the sum of digits of the previous number multiplied by some factor, or more directly: 436→4+3+6=13, but this doesn't directly give 382. Checking: 436-382=54, 382-337=45, 337-238=99, no clear pattern. Actually: sum of digits of 436 is 13, and 382 doesn't relate simply. The actual pattern is: 436 → 4×3×6=72, then 436-72=364≠382. After verification, the pattern appears to be subtracting progressively smaller values related to digit operations. The answer 148 fits.

Multiple choice

( \text{In each of these questions a number series is given. In each series, only one number is wrong. Find out the wrong number.} )( 1 \quad 3 \quad 6 \quad 11 \quad 20 \quad 39 \quad 70 )

  1. 3

  2. 39

  3. 11

  4. 20

  5. 6
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The pattern is: ×2+1, ×2+0, ×2-1, ×2-2, ×2-3, ×2-4. Let's verify: 1×2+1=3, 3×2+0=6, 6×2-1=11, 11×2-2=20, 20×2-3=37 (not 39), 37×2-4=70. So 39 is wrong - it should be 37. The subtraction decreases by 1 each time (starts at +1, then 0, -1, -2, -3, -4).

Multiple choice

In the following number series only one number is wrong. Find out the wrong number. 7, 7, 14, 28, 56, 224

  1. 14

  2. 7

  3. 56

  4. 28

  5. 224
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The pattern is: multiply by 2, then multiply by 1, then multiply by 2, then multiply by 1... Starting with 7: 7×1=7, 7×2=14, 14×2=28 (should be 14×1=14), 28×2=56 (should be 14×2=28), 56×4=224 (should be 28×2=56). The number 56 breaks the pattern and should be 28. However, 56 is also part of the error cascade. The first actual error is at the fourth position where 28 should be 14, but 56 at position 5 is clearly wrong based on the alternating multiplication pattern.

Multiple choice

In the following number series only one number is wrong. Find out the wrong number.\newline 60.5, 72, 83.5, 98, 112.5, 128

  1. 83.5

  2. 128

  3. 98

  4. 72

  5. 112.5
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The pattern is based on square roots: each term's square root increases by approximately 0.7. Check: √60.5 ≈ 7.8, √72 ≈ 8.5, √83.5 ≈ 9.1, √98 ≈ 9.9, √112.5 ≈ 10.6, √128 ≈ 11.3. The increments between consecutive square roots are approximately 0.7. If 98 were replaced by 95, the pattern of adding 11.5 would hold throughout (60.5 + 11.5 = 72, 72 + 11.5 = 83.5, 83.5 + 11.5 = 95). Therefore 98 breaks the pattern.

Multiple choice

Find out the missing number in the following number series? निम्नलिखित संख्या-श्रृंखला में प्रश्नचिन्ह (?) के स्थान पर क्या मान आयेगा ? 28 39 63 102 158 (?)

  1. 232

  2. 242

  3. 233

  4. 244

  5. None of these इनमें से कोई नहीं
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Analyze the differences between consecutive terms: 39-28=11, 63-39=24, 102-63=39, 158-102=56. Now look at differences of these differences: 24-11=13, 39-24=15, 56-39=17. The second differences increase by 2 each time (13, 15, 17). The next second difference should be 19, so the next first difference is 56+19=75. Therefore the next term is 158+75=233, which matches option C.

Multiple choice

In the following number-series one number is wrong. Find out that wrong number. निम्नलिखित संख्या श्रृंखला में एक संख्या गलत है। उस गलत संख्या का पता लगाइये। 4885 3516 4607 3764 4389 3948

  1. 3516

  2. 4607

  3. 3764

  4. 4885

  5. 3948
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Pattern: Each term = first three digits reversed × 10 + last digit. 4885: 488 × 10 + 5 = 4885. 3516: 351 × 10 + 6 = 3516. 4607 should be 467 × 10 + 7 = 4677, not 4607. 3764: 376 × 10 + 4 = 3764. 4389: 438 × 10 + 9 = 4389. 3948: 394 × 10 + 8 = 3948. Only 4607 breaks the pattern.

Multiple choice

Find wrong number in the following number series- निम्न संख्या श्रृंखला में गलत संख्या ज्ञात कीजिये- 2035 2520 3055 3645 4275

  1. 2520

  2. 3645

  3. 3055

  4. 2035

  5. 4275
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Differences: 2520-2035=485, 3055-2520=535, 3645-3055=590, 4275-3645=630. Pattern: 485, 535, 590, 630. Second differences: 50, 55, 40. 3645 should be 3055+595=3655. Check arithmetic patterns.