In each series, look for the degree and direction of change between the numbers. In other words, do the numbers increase or decrease, and by how much
Answer: Option D
8 x 1 - 2 = 6
6 x 2 - 3 = 9
9 x 3 - 4 = 23
23 x 4 - 5 = 87
87 x 5 - 6 = 429 ...
In this simple subtraction series, each number decreases by 0.4.
Answer: Option C
This is a simple multiplication series. Each number is 3 times more than the previous number.
Answer: Option A
This is an alternating addition and subtraction series. In the first pattern, 10 is subtracted from each number to arrive at the next. In the second, 5 is added to each number to arrive at the next.
This is a simple subtraction series. Each number is 35 less than the previous number.