- 1. Which number would replace underline mark in the series?

2, 5, 10, 17, ---, 37

**Answer: Option 'C'**

**Here the difference between the consecutive terms is increase by 2
5 - 2 = 3,
10 - 5 = 5,
17 - 10 = 7,
then 17 + 9 = 26.**

- 2. Which number would replace underline mark in the series?

1, 6, 26,_____, 426.

**Answer: Option 'C'**

**Here the difference between the consecutive terms is multiplied by 4.
The difference of the two consecutive numbers is 5, 20, .....
5 × 4 = 20
20 × 4 = 80
26 + 80 = 106.**

- 3. Which number would replace underline mark in the series?

1, 20, 58, ____, 191.

**Answer: Option 'B'**

**Here the difference between the two consecutive terms is 19, 38, 57, 76
58 + 57 = 115**

- 4. 2, 10, 40, 120,____

**Answer: Option 'A'**

**Here the series is a multiplication series.
The order of the multiplication is ×5, ×4, ×3, ×2
120 × 2 = 240**

- 5. 18 21 25 18 29 33 18

What numbers should come next ?

**Answer: Option 'C'**

**This is a simple addition series with a random number, 18, interpolated as every third number.
In the series, 4 is added to each number except 18, to arrive at the next number**

- 6. 20 20 17 17 14 14 11 What numbers should come next ?

**Answer: Option 'C'**

**This is a simple subtraction with repetition series.
It begins with 20, which is repeated, then 3 is subtracted, resulting in 17, which is repeated, and so on.
Rule = (1st no) (1st no) (1st no - 3 = 2nd no) (2nd no repeat) (2nd no - 3 = 3rd no) (3rd no repeat). . .
Now (20) (20) (20 - 3 = 17) (17) (17 - 3 = 14) (14) (14 - 3 = 11) (11) (11 - 3 = 8) (8)
So the answer is e = 11 8.**

- 7. 3 13 18 23 28 33

What number should come next?

**Answer: Option 'A'**

**In this simple addition series, each number is 5 greater than the previous number.
Rule = (1st no) (1st no + 5 = 2nd no) (2nd no + 5 = 3rd no) . . .
Now (3) (3 + 5 = 8) (8 + 5 = 13) (13 + 5 = 18) (18 + 5 = 23) (23 + 5 = 28) (28 + 5 = 33) (33 + 5 = 38) (38 + 5 = 43)
So the answer is c = 38 43**

- 8. Look at this series: 1000, 200, 40, . . .

What number should come next?

**Answer: Option 'B'**

**This is a simple division series.
Each number is divided by 5.
Rule = (1st number / 5 = 2nd number) (2nd number / 5 = 3rd number)....
Now, (1000 / 5 = 200), (200 / 5 = 40), (40 / 5 = 8)...
So answer is a = 8.**

- 9. Look at this series: 7, 10, 8, 11, 9, 12, . . .

What number should come next?

**Answer: Option 'B'**

**This is a simple alternating addition and subtraction series.
In the first pattern, 3 is added;
In the second pattern, 2 is subtracted.
Rule =(1st number) (1st number + 3 = 2nd number) (2nd number - 2 = 3rd number) (3rd number + 3 = 4th number)
Now (7) (7 + 3 = 10) (10 - 2 = 8) (8 + 3 = 11) (11 - 2 = 9) (9 + 3 = 12) (12 - 2 = 10)...
So the answer is b = 10.**

- 10. 1, 2, 3, 10, ____, 9802

**Answer: Option 'C'**

**1 ^{2} + 1 = 2
2^{2} - 1 = 3
3^{2} + 1 = 10
10^{2} - 1 = 99.**

- 11. 2, 10, 26, 50, ___, 122.

**Answer: Option 'A'**

**Here the series of the form (1 ^{2} + 1), (3^{2} + 1), (5^{2} + 1), .......**

- 12. Look at this series: 14, 28, 20, 40, 32, 64, . . .

What number should come next ?

**Answer: Option 'B'**

**This is an alternating multiplication and subtracting series: First, multiply by 2 and then subtract 8.
Rule = (1st no.) (1st x 2 = 2nd no.) (2nd - 8 = 3rd no.) (3rd x 2 = 4th no.)....
Now (14) (14 x 2 = 28) (28 - 8 = 20) (20 x 2 = 40) (40 - 8 = 32) (32 x 2 = 64) (64 - 8 = 56)...
So the answer is b = 56.**

- 13. Look at this series: 5.2, 4.8, 4.4, 4, . . .

What number should come next?

**Answer: Option 'B'**

**In this simple subtraction series, each number decreases by 0.4.
Rule = (1st no.) (1st no. - 0.4 = 2nd no.) (2nd no. - 0.4 = 3rd number)...
Now (5.2) (5.2 - 0.4 = 4.8) (4.8 - 0.4 = 4.4) (4.4 - 0.4 = 4) (4 - 0.4 = 3.6) ...
So the answer is d = 3.6**

- 14. 84 78 72 66 60 54 48

What number should come next ?

**Answer: Option 'B'**

**In this simple subtraction series, each number is 6 less than the previous number.
Rule = (1st number) (1st no - 6 = 2nd no.) (2nd no - 6 = 3rd no). . .
Now (84) (84 - 6 = 78) (78 - 6 = 72) (72 - 6 = 66) (66 - 6 = 60) (60 - 6 = 54) (54 - 6 = 48) (48 - 6 = 42) (42 - 6 = 36).
So the answer is b = 42 36**

- 15. Look at this series: 3, 4, 7, 8, 11, 12, . . .

What number should come next ?

**Answer: Option 'C'**

**This alternating addition series begins with 3;
then 1 is added to give 4;
then 3 is added to give 7;
then 1 is added, and so on.
Rule = (first number + 1) (second number + 3) (third number + 1) (fourth number + 3)...
Now The series is 3, 4, 7, 8, 11, 12...
(3 + 1 = 4), (4 + 3 = 7), (7 + 1 = 8), (8 + 3 = 11), (11 + 1 = 12) (12 + 3 = 15)...
So the answer is d = 15.**

- 16. Look at this series: 31, 29, 24, 22, 17, . . .

What number should come next?

**Answer: Option 'A'**

**This is a simple alternating subtraction series, which subtracts 2, then 5.
Rule = (first number - 2) (second number - 5) (third number - 2) (fourth number - 5)...
Now The series is 31, 29, 24, 22, 17, . . .
(31 - 2 = 29), (29 - 5 = 24), (24 - 2 = 22), (22 - 5 = 17), (17 - 2 = 15)...
So the answer is a = 15.**

- 17. Find the wrong number in the series.

1, 2, 6, 15, 31, 56, 91

**Answer: Option 'D'**

**The difference odd the two consecutive numbers are
1, 4, 9, 16, 25, 35.
+1**

- 18. Find the wrong number in the series.

2, 5, 10, 17, 26, 37, 50, 64

**Answer: Option 'C'**

**1 ^{2} + 1, 2^{2} + 1, 3^{2} + 1 ..........8^{2} + 1 = 65 **

But 64 has been given here. So our wrong number is 64

- 19. Find the missing number in the following series.

512, 256, 64, 32, ?

**Answer: Option 'C'**

**512/2 = 256
256/4 = 64
64/2 = 32
32/4 = 8.**

- 20. Find the missing number in the following series.

2, 3, 6, 15, 45, ?

**Answer: Option 'D'**

**2 × 1.5 = 3
3 × 2 = 6
6 × 2.5 = 15
15 × 3 = 45
45 × 3.5 = 157.5**

- 21. Find the missing number in the following series.

376, 188, 47, 23.5, ?

**Answer: Option 'C'**

**367/2 = 188
188/4 = 47
47/2 = 23.5
23.5/4 = 5.8**

- 22. Find the missing number in the following series.

1050, 506, 236, 105, ?

**Answer: Option 'D'**

**1050/2 = 525 - 19 = 506
506/2 = 253 - 17 = 236
236/2 = 118 - 13 = 105
105/2 = 52.5 - 11 = 41.5**

- 23. Find the missing number in the following series.

12, 53, 207, 618, ?

**Answer: Option 'C'**

**12 × 5 - 7 = 53
53 × 4 - 5 = 207
207 × 3 - 3 = 618
618 × 2 - 2 = 1234.**

- 24. Look at the series 3, 3/2, 3/4, 3/6 … what number should come next?

**Answer: Option 'A'**

**3/8**

- 25. Look at the series 2, 3, 5, 8, 12….. What number should come next?

**Answer: Option 'D'**

**17**

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