## Number Series Questions and Answers Part-16

1.Find the missing term :- 2, 3, 3, 5, 10, 13, ?, 43, 172, 177
a) 23
b) 38
c) 39
d) 40

Explanation: The pattern is + 1, × 1, + 2, × 2, + 3, × 3, + 4, × 4, + 5
So, missing term = 13 × 3 = 39

2. Find the missing term: 563, 647, 479, 815, ?
a) 672
b) 386
c) 279
d) 143

Explanation: The pattern is + 84, - 168, + 336, .....i.e., + 84, - (84 × 2), + (84 × 22 ),.................
So, missing term = 815 - (84 × 23 ) = 815 - 672 = 143

3. Find the missing term, 4, 9, 25, ?, 121, 169, 289, 361
a) 49
b) 64
c) 81
d) 87

Explanation: The given series consists of squares of consecutive prime numbers i.e., 22 , 32 , 52 ,.....................,112 , 132 , 172 , 192
So, missing term = 72 = 49

4. Find the missing term :- 240, ?, 120, 40, 10, 2
a) 180
b) 240
c) 420
d) 480

Explanation: The pattern is ÷ 1, ÷ 2, ÷ 3, ÷ 4, ÷ 5
So, missing term = 240 ÷ 1 = 240

5. Find the missing term :- 1, 9, 25, 49, 81, ?
a) 100
b) 112
c) 121
d) 144

Explanation: The series consists of squares of consecutive odd numbers i.e., 12 , 32 , 52 , 72 , 92 ,..............
So, missing term = 112 = 121

6. Find out the wrong term: 5, 27, 61, 122, 213, 340, 509
a) 27
b) 61
c) 122
d) 509

Explanation: The terms of the series are (23 - 3), (33 - 3), (43 - 3), (53 - 3), (63 - 3), (73 -3), (83 -3).
So, 27 is wrong and must be replaced (33 - 3) i.e., 24

7. Find out the wrong term: 6, 15, 35, 77, 165, 221
a) 35
b) 77
c) 165
d) 221

Explanation: The terms of the series are product of two consecutive prime numbers i.e., (2 × 3), (3 × 5), (5 × 7), (7 × 11),...........
So, 165 is wrong and must be replaced by (11 × 13) i.e., 143.

8. Find out the wrong term: 121, 143, 165, 186, 209
a) 143
b) 165
c) 186
d) 209

Explanation: Each term in the series is obtained by adding 22 to the preceding term.
So, 186 is wrong and must be replaced by (165 + 22) i.e., 187.

9. Find out the wrong term: 24576, 6144, 1536, 386, 96, 24
a) 96
b) 386
c) 1536
d) 6144