Number Series Questions

Multiple choice
  1. 89

  2. 163

  3. 117

  4. 80

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

The differences are: 80-76=4, 89-80=9, 117-89=28, 163-117=46, 284-163=121. Looking at the differences: 4, 9, 28, 46, 121. The difference of differences: 9-4=5, 28-9=19, 46-28=18, 121-46=75. The pattern breaks at 117. If 117 were correct, the sequence would follow a smoother pattern.

Multiple choice
  1. 11

  2. 17

  3. 67

  4. 35

  5. None of these

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

The pattern is: ×2, ×2+1, ×2-1, ×2-1, ×2-1. Starting with 11: 11×2=22 (should be 17, error here), 17×2+1=35, 35×2-1=69 (but we have 67), 69×2-1=137 (but we have 144), 137×2-1=273 (but we have 287). The term 35 breaks the established pattern and should be 22. Alternatively, checking differences: 6, 18, 32, 77, 143 - no clear pattern. The series likely should be 11, 23, 35, 67, 135, 267 or 11, 22, 45, 89, 177, 353.

Multiple choice
  1. 126

  2. 4410

  3. 42

  4. 48510

  5. None of these

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

Checking patterns: 21×2=42, 42×3=126, 126×5=630 (but we have 620, error here), 630×7=4410, 4410×11=48510. The pattern uses consecutive prime numbers (2, 3, 5, 7, 11) as multipliers. 620 breaks this pattern - it should be 630. All other terms fit the pattern correctly.

Multiple choice
  1. 1737

  2. 2575

  3. 1007

  4. 517

  5. None of these

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

The pattern is (n+1)^3 + n where n starts at 4: 4^3+4=68, 5^3+5=130, 6^3+6=222, 7^3+7=350, 8^3+8=520. Checking: 65→68(diff+3), 68→130(diff+62), 130→222(diff+92), 222→350(diff+128), 350→520(diff+170), 520→737(diff+217). The actual series is 65→219(diff+154), 219→517(diff+298), 517→1007(diff+490), 1007→1737(diff+730), 1737→2755(diff+1018). The term 2575 breaks the pattern; it should be 2755.

Multiple choice
  1. 97.25

  2. 92.5

  3. 101

  4. 86

  5. 116

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

The series follows a pattern: +60, -30, +15, -7.5. Starting from 56: 56+60=116, 116-30=86, 86+15=101, 101-7.5=93.5. But the given term is 92.5 instead of 93.5. The pattern alternates between adding and subtracting half of the previous difference (60, 30, 15, 7.5). The wrong term is 92.5.

Multiple choice
  1. 499

  2. 491

  3. 464

  4. 498

  5. 400

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

The series follows the pattern: subtract consecutive cubes. 498-1³=497 (not 499), 499-2³=491, 491-3³=464, 464-4³=400, 400-5³=275. The pattern should be subtracting 1³, 2³, 3³, 4³, 5³. Since 498 is the starting point, the wrong term is 498 - the pattern should start from 498-1³=497, making the first term 497, not 498.

Multiple choice
  1. $1945$
  2. $1948$
  3. $1749$
  4. $4096$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The pattern is n³ + n: 3³+3=30, but the second term is 4. Let's re-examine: 3 to 4: 3×1+1=4, 4 to 16: 4×4=16, 16 to 75: 16×4+11=75, 75 to 364: 75×4+64=364. The actual pattern is n³ - n + some adjustment. Starting from 3: 3³-3=24 (not 4). The correct pattern is n³ - n for terms starting from 3, then 4³-4=60 (not 16). Wait - the pattern is n³ - 7, n² - 1... Let's verify: For n=13: 13³ - 13 = 2197 - 13 = 2184. The series follows: 3, 4, 16, 75, 364, 1945. Pattern: n³ - n + 2 for n=3 gives 24+2=26. Not matching. The actual pattern is n³ - n - 8: 3³-3-8=16 (not 3 or 4). Starting from second term: 4³-4=60 (not 16). The correct pattern is: multiply by 4 and add 4, then multiply by 5 and subtract 5, alternating. 3×4+4=16, 16×4+11=75, 75×4+64=364, 364×5+145=1945. For option A (1945): 364×5+145=1945 ✓

Multiple choice
  1. 320

  2. 160

  3. 600

  4. 2100

  5. 9000

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

The pattern is: divide by 4, then add 300 to get the next term. Starting from 9000, we get 9000/4 + 300 = 2550, not 2100. However, the series continues with 2100/4 + 300 = 825, not 600. The series appears to follow: term/4 + 300, but 9000 doesn't fit the reverse pattern from 600 (which would require 600 x 4 - 300 = 2100).

Multiple choice
  1. 2.5

  2. 6.25

  3. 15.625

  4. 1

  5. 19.62625

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

The pattern appears to be: multiply by 2.5, then add or subtract a calculated value. Starting from 1: 1 x 2.5 = 2.5 (correct). For 2.5: 2.5 x 2.5 = 6.25, but the next term should be 6.25 + 6.25/2.5 - some adjustment. The pattern isn't perfectly clear, but 19.62625 doesn't fit the progression from 15.625.

Multiple choice
  1. 1354

  2. 191

  3. 37

  4. 11

  5. 9

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

The pattern is n × 2 + (sum of digits of n): 9×2+9=27, 27×2+(2+7)=54+9=63, 63×2+(6+3)=126+9=135, 135×2+(1+3+5)=270+9=279, 279×2+(2+7+9)=558+18=576. The series should be 9, 27, 63, 135, 279, 576. The given 191 breaks the pattern, and 1354 is also incorrect (should be 135). The wrong number is 1354.