4, -8, 16, -32, 64, (....)
Answer: Option B
Explanation:
Each number is the proceeding number multiplied by -2.
So, the required number is -128.
11, 13, 17, 19, 23, 29, 31, 37, 41, (....)
Answer: Option A
7, 26, 63, 124, 215, 342, (....)
Numbers are (23 - 1), (33 - 1), (43 - 1), (53 - 1), (63 - 1), (73 - 1) etc.
So, the next number is (83 - 1) = (512 - 1) = 511.
2, 6, 12, 20, 30, 42, 56, (....)
Answer: Option C
The pattern is 1 x 2, 2 x 3, 3 x 4, 4 x 5, 5 x 6, 6 x 7, 7 x 8.
So, the next number is 8 x 9 = 72.
8, 24, 12, 36, 18, 54, (....)
Numbers are alternatively multiplied by 3 and divided by 2.
So, the next number = 54 � 2 = 27.
