##### Number Series

Prime Number Series

Q1. 4,9,25,29,121,169,_____

a) 324

b) 289

c) 225

d) 196

Solution: b (Given Series is square of consecutive prime numbers). So 169 is square of 13 and the next prime number is 17. 17square is 289 so the correct answer is 289.)

Q2. 5, 7, 13, 23,____

a) 25

b) 27

c) 29

d) 41

Solution: d (The differences between the prime numbers are increasing. 7 is the next prime number after 5, 13 is second next prime number after 7, 23 is the third next prime number after 13. Hence the fourth next prime number after 23 is the answer which is 41.) Multiplication Series

Q3. 4,8,16,32,64,____,256

a) 128

b) 98

c) 86

d) 106

Solution: a (The numbers are multiplied by 2 to get the next number. Hence the number is 64 X 2 = 128)

Q4. 5, 20, 80, 320, 1280, _____

a) 5120

b) 5220

c) 4860

d) 3642

Solution: a (The number are multiplied by 4 to get the next number. Hence the next number is 1280 X 4 = 5120) Difference Series

Q5. 3,6,9,12,15,___,21

a) 16

b) 17

c) 20

d) 18

Solution: d (The difference between the numbers is 3. Hence the next number is 15 + 3 = 18)

Q6. 55, 50, 45, 40, ____, 30

a) 33

b) 34

c) 35

d) 36

Solution: c (The difference between the numbers is -5. Hence the next number is 40 � 5 = 35) Division Series

Q7. 5040, 720, 120, 24, ___, 2, 1

a) 8

b) 7

c) 6

d) 5

Solution: c (5040/7 = 720, 720/6=120, 120/5=24, 24/4=6, 6/3=2, 2/2=1)

Q8. 16, 24, 36, ___, 81

a) 52

b) 54

c) 56

d) 58

Solution: b (Previous Number X = Next Number, So 36 X = 54) n2 Series

Q9. 4, 16, 36, 64, ____, 144

a) 112

b) 78

c) 100

d) 81

Solution: c (The series is square of consecutive even number. 22, 42, 62, 82, 102, 122)

Q10. 1, 4, 9, 16, 25, 36, 49, ____, 81

a) 100

b) 121

c) 64

d) 144

Solution: c (The series is 12, 22, 32, 42, 52, 62, 72, 82, 92) (n2 + 1) Series

Q11. 17, 26, 37, 50, 65, ____, 101

a) 82

b) 75

c) 78

d) 90

Solution: a (The series is 42+1, 52+1, 62+1, 72+1, 82+1, 92+1, 102+1, so the missing number is 92+1 = 82)

Q12. 101, 401, 901, 1601, 2501, ____, 4901

a) 2201

b) 3301

c) 4401

d) 3601

Solution: d (The series is 102+1, 202+1, 302+1, 402+1, 502+1, 602+1, 702+1, so the missing number is 602+1 = 3601) (n2 – 1) Series

Q13. 3, 8, 15, 24, ____, 48

a) 32

b) 33

c) 34

d) 35

Solution: d (The series is 22-1, 32-1, 42-1, 52-1, 62-1, 72-1. So the number is 62-1 = 35)

Q14. 99, 80, 63, ___, 35

a) 48

b) 84

c) 46

d) 64

Solution: a ( The series is 102-1, 92-1, 82-1, 72-1, 62-1. So the number is 72-1 = 48) (n2 + n) Series

Q15. 2, 6, 12, 20, 30, ___, 56

a) 32

b) 34

c) 42

d) 24

Solution: c (The series is 12+1, 22+2, 32+3, 42+4,52+5, 62+6, 72+7. Hence the number is 62+6 = 42)

Q16. 110, 132, 156, 182, _____

a) 212

b) 201

c) 211

d) 210

Solution: d (The series is 102+10, 112+11, 122+12, 132+13, 142+14. So the number is 142+14 = 210) (n2 � n) Series

Q17. 0, 2, 6, 12, 20, ____, 42

a) 25

b) 30

c) 32

d) 40

Solution: b ( The series is 12-1, 22-2, 32-3, 42-4, 52-5, 62- 6, 72- 7. So the missing number is 62 – 6 = 30)

Q18. 90, 380, 870, 1560, ____

a) 2405

b) 2450

c) 2400

d) 2455

Solution: b (The series is 102-10, 202-20, 302-30, 402-40, 502-50, so the number is 502 � 50 = 2450) n3 Seires

Q19. 1, 8, 27, 64, ____, 216

a) 125

b) 512

c) 215

d) 122

Solution: a (The series is 13, 23, 33, 43, 53, 63, so the number is 53 = 125) Content of logical reasoning is contributed by The Knowledge Tree (Best CLAT Coaching). The Knowledge Tree also conduct classroom coaching classes and crash courses for CLAT 2015.