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.