30-08-2021 Answers

1. Choose the option to replace the question mark in the below number series.

4, 9, 19, 34, 54, ?, 109

Answer: 79

Solution: The difference between adjacent terms is like 5,10,15,20,25,30,35 and so on.

So 54+25=79

2. Choose the option to replace the question mark in the below number series.

5, 3, 6, 2, 7, 1, ?

Answer: 8

Solution: Two sequences are intermingled.

First sequence at odd positions is like 5,6,7,...

Second at even positions is like 3,2,1,...

So ? = 8

3. Choose the option to replace the question mark in the below number series.

5, 4, 9, 81, 79, 320, 20, 11, ?

Answer: 279

Solution: For every three terms, third is the difference between square of first term minus square of second term

9 = 5^2 - 4^2, 320 = 81^2 - 79^2.

? = 20^2 - 11^2 = 279

4. Choose the option to replace the question mark in the below number series.

1, 3, 6, 11, 18, 29, ?

Answer: 42

Solution: Starting from 1, the prime numbers from 2 are added to get the next term.

1 + 2 =3,

3 + 3 =6,

6 + 5 =11 and so on.

So ? = 29+13 = 42

5. Choose the option to replace the question mark in the below number series.

9, 81, 90, 810, 819, ?

Answer: 7371

Solution: For every three terms, second term is first term multiplied by 9, third is second + 9

That is, 9*9=81, 81+9=90, 90*9 = 810, 810+9=819, ?=819*9 = 7371

6. Choose the option to replace the question mark in the below number series.

3, 6, 15, ?, 123, 366

Answer: 42

Solution: The difference between two consequent terms differs by power of 3 in increasing order.

6-3 = 3^1, 15-6=3^2, So ? - 15 = 3^3, ? = 27+15 = 42

7. Choose the option to replace the question mark in the below number series.

1, 5, 21, ?, 341

Answer: 85

Solution: Power of 4 starting from 1 is being added to the previous term.

1 + 4^1 = 5

5 + 4^2 = 21

21+ 4^3 = 85

8. Choose the option to replace the question mark in the below number series.

4, 8, 7, 7, 10, 6, 13, 5, ?

Answer: 16

Solution: Two series intermingled. First is a +3 series at odd positions is like 4,7,10,13,16,...

Second is a -1 series at even positions like 8,7,6,5,4,...

So ? = 13+3 = 16

9. Choose the option to replace the question mark in the below number series.

2, 4, 8, 3, 9, 27, 4, 16, ?

Answer: 64

Solution: 2,4,8 is two followed by it's square and cube.

3,9,27 is three followed by it's square and cube.

So ? = 4^3 = 64

10. Choose the option to replace the question mark in the below number series.

80, 64, 48, 32, 16, ?

Answer: 0

Solution: 8*10=80, 8*8=64, 8*6=48, 8*4=32, 8*2=16, 8*0=?=0

11. Choose the option to replace the question mark in the below number series.

23, 29, 31, 37, ?, 43

Answer: 41

Solution: List of prime numbers starting from 23.

So the prime number after 37 is 41.

12. Choose the option to replace the question mark in the below number series.

45, 54, 57, 75, 79, ?

Answer: 97

Solution: Even term is the reverse of the previous odd term.

So 79 reversed is 97

13. Choose the option to replace the question mark in the below number series.

5, 16, 49, 104, ?

Answer: 181

Solution: The difference between adjacent terms is like 11,33,55,77 and so on.

So ? = 104+77 = 181

14. Choose the option to replace the question mark in the below number series.

4, 32, 128, ?

Answer: 256

Solution: 4  = 2^2,

32 = 2^5

128= 2^7. (That is the power of 2 decreases by one for each subsequent term)

? = 2^8 = 256

15. Choose the option to replace the question mark in the below number series.

2, 10, 30, 68, ?

Answer: 130

Solution: 1^3 + 1 = 2,

2^3 + 2 = 10,

3^3 + 3 = 30,

4^3 + 4 = 68,

? = 5^3 + 5 = 130