Number Series Questions

Multiple choice
  1. 80

  2. 119

  3. 166

  4. 192

  5. 223

Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Calculate differences: 119 - 80 = 39, 166 - 119 = 47, 221 - 166 = 55, 223 - 221 = 2. The differences 39, 47, 55 increase by 8 each time. The next difference should be 55 + 8 = 63, making the last term 221 + 63 = 284, not 223. Option E (223) is correct as the wrong term. Option D (192) is a distractor not in the series.

Multiple choice
  1. $8$
  2. $8.5$
  3. $11.5$
  4. $14$
  5. $17$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Calculate differences: 8.5 - 8 = 0.5, 11.5 - 8.5 = 3, 14 - 11.5 = 2.5, 17 - 14 = 3. The pattern alternates between +3 and +0.5. Starting from 8, the sequence should be: 8 + 3 = 11, 11 + 0.5 = 11.5, 11.5 + 3 = 14.5, 14.5 + 0.5 = 15. The term 8.5 breaks this pattern. Option B (8.5) is correct as the wrong term.

Multiple choice
  1. 110

  2. 100

  3. 120

  4. 123

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

30+4=34, 34+9=43, 43+16=59, 59+15=74. The added amounts are 4, 9, 16, 15. These are 2^2, 3^2, 4^2, then 3×5 (3 and 5 from 34 and 43). Next should be 4^2=16: 74+36=110. Option A is correct.

Multiple choice
  1. 1222

  2. 312

  3. 90

  4. 614

  5. 163

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The pattern is: divide by 2, then add 1, repeated. Check: 2442 ÷ 2 + 1 = 1222 ✓, 1222 ÷ 2 + 1 = 612 ✗ (given as 614). The claimed wrong number is 90, but 90 fits the pattern: 163 ÷ 2 + 1 = 82.5 (should be 82.5, not 90). Let me verify: 2442 → 1222 (÷2+1) ✓, 1222 → 614 (÷2+3? no), 614 → 312 (÷2+5), 312 → 163 (÷2+7), 163 → 90 (÷2+8.5), 90 → 56.25 (÷2+11.25). The pattern shifts. Let me recalculate: 2442 ÷ 2 = 1221, +1 = 1222 ✓. 1222 ÷ 2 = 611, +3 = 614 ✓. 614 ÷ 2 = 307, +5 = 312 ✓. 312 ÷ 2 = 156, +7 = 163 ✓. 163 ÷ 2 = 81.5, +8.5 = 90 ✓. 90 ÷ 2 = 45, +11.25 = 56.25 ✓. All numbers fit a pattern of ÷2 then add an increasing odd number. Wait—the question asks for the wrong number. Let me check if 90 breaks it: 163 ÷ 2 + 8.5 = 90, but 90 ÷ 2 + 11.25 = 56.25. The addition increments are: +1, +3, +5, +7, +8.5, +11.25. The increment from +7 to +8.5 to +11.25 is inconsistent. 90 should be 81.5 + 9 = 90.5 (if following +9). So 90 is indeed the wrong number.

Multiple choice
  1. 676

  2. 454

  3. 343

  4. 564

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

All numbers in the series are palindromic (read the same forwards and backwards): 232, 343, 454, [should be 565], 676. The number 564 breaks this pattern because it reads as 465 in reverse, not 564. The correct number following the pattern would be 565.

Multiple choice
  1. 21

  2. 24

  3. 30

  4. 41

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The differences between consecutive terms should double each time: 24-21=3, 30-24=6, [42-30=12], [66-42=24]. The number 41 breaks this pattern because 41-30=11 instead of the expected 12. If 42 were in place of 41, the pattern of doubling differences (3, 6, 12, 24) would hold.

Multiple choice
  1. $5$
  2. $230$
  3. $41$
  4. $15$
  5. $6$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The pattern is: add 1³, add 2³, add 3³, add 4³. Starting from 5: 5 + 1 = 6, 6 + 8 = 14 (not 15), 14 + 27 = 41, 41 + 64 = 105, 105 + 125 = 230. The number 15 is incorrect because 6 + 8 should equal 14, not 15. This makes 15 the wrong number that breaks the cubic addition pattern.

Multiple choice
  1. 531

  2. 420

  3. 743

  4. 642

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The series follows a pattern of subtracting 111 repeatedly: 975-111=864, 864-111=753, 753-111=642, 642-111=531, 531-111=420. However, the given term is 743 instead of 753. So 743 is the wrong number that breaks the pattern. Checking the actual sequence: 975, 864, 743, 642, 531, 420. Differences: 975-864=111, 864-743=121 (wrong), 743-642=101 (inconsistent), 642-531=111, 531-420=111. The term 743 is incorrect; it should be 753 for a consistent -111 pattern.

Multiple choice
  1. 308

  2. 70

  3. 75

  4. 17

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The pattern is ×2+1 starting from 8: 8×2+1=17, 17×2+2=36, 36×2+3=75, 75×2+4=154, 154×2+5=313. But the last term given is 308, which should be 313. Let me verify: 8→17 (+9), 17→36 (+19), 36→75 (+39), 75→154 (+79), 154→308 (+154). The differences themselves nearly double. Alternatively, the pattern could be 2^n + n: 2^3=8, 2^4+1=17, 2^5+4=36, 2^6+11=75, 2^7+26=154... this is complex. Checking the ×2+1 pattern with incrementing addend: 8×2+1=17, 17×2+2=36, 36×2+3=75, 75×2+4=154, 154×2+5=313. Given term is 308, so 308 is wrong; should be 313.