Look at this series: 36, 34, 30, 28, 24, …. What number should come next?
A. 20
B. 22
C. 23
D. 26

Hint: we have to carefully analyze the series given in question and find the change in every next digit. In the above series we can see that there is reduction of 2 numbers and 4 numbers after every digit. So, we will find the next digit by reducing some numbers from the last digit.

Complete step by step answer:
This is an alternating number subtraction series.
$36 - 34 = 2$
$34 - 30 = 4$
$30 - 28 = 2$
$28 - 24 = 4$
In this series first, 2 is subtracted from the first digit then 4 is subtracted from the next digit then again 2 is subtracted from next digit then again 4 is subtracted …. And so on.
So, according to this we have to subtract the digit 24 by 2 to get the correct answer.
$24 - 2 = 22$
The number that should come next is 22.

So, the correct answer is “Option B”.

Note:
Alternating number subtraction series is a number series in which a constant amount of number or numbers are subtracted from each digit of the series.
For example: We are given a series like 18, 15, 12, 9, 6 …. And so on. And we are asked to find the next digit. By analyzing this above series we find that each digit is subtracted by 3. So, the next digit will be 3 subtracted from the last digit which is 6. So, 6 – 3 = 3. The next digit will be 3.