Find the missing number

Find the missing number in the following sequences:

1) 61, 52, 63, 94, __ , 18, 001, 121

[CSIR NET, June, 2014, Mathematical Sciences.]

A) 46 B) 70 C) 64 D) 44

2) 4, 2, 6, 8, 14, __ , 36

A) 16 B) 12 C) 22 D) 30

3) 72, 46, __ , 612, 343

A) 105 B) 521 C) 703 D) 13

4) 1, 3, 6, 8, 16, 18, 36, __ , 76

A) 74 B) 72 C) 38 D) 42

5) 1, 2, 4, 7, 11, __ , 22

A) 16 B) 18 C) 17 D) 12

6) 3, 5, 7, 11, __ , 17

A) 17 B) 14 C) 15 D) 13

7) 1, 6, 16, 31, __ , 76, 106

A) 61 B) 51 C) 36 D) 32

8) 2, 6, 12, 20, 30, __ , 56

A) 44 B) 36 C) 42 D) 48

9) 1, 3, 7, 2, 6, 10, 3, __ , 13

A) 11 B) 9 C) 7 D) 5

10) 1, 1, 3, 15, __ 945

A) 25 B) 95 C) 75 D) 105

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Answers:

1) A) [Hint:- 61, 52, 63, 94, __ , 18, 001, 121 -> 16, 25, 36, 49, __ , 81, 100, 121.]

2) C) [Hint:- 4+2=6, 2+6=8 etc.]

3) B) [Hint:- 72, 46, __ , 612, 343 -> 27, 64, __ , 216, 343]

4) C) [Hint:- 1+2=3, 3×2=6, 6+2=8, 8×2=16 etc.]

5) A) [Hint:- 1+1=2, 2+2=4, 4+3=7, 7+4=11 etc.]

6) D) [Hint:- Odd prime numbers in order.]

7) B) [Hint:- The difference between two consecutive terms are increased by 5.]

8) C) [Hint:- Multiplication of two consecutive natural numbers.]

9) B) [Hint:- 1, 3, 7, 2, 6, 10, 3, __ , 13 -> 1,2,3 ; 3,6, __ ; 7,10,13]

10) D) [Hint:- 1×1=1, 1×3=3, 3×5=15, 15×7=105, 105×9=945]