Answer: What Comes Next? #318

The answer is B: 21.

The rule

Take away 4 each time.

The pattern as Python code

Here is a tiny Python program that follows the same rule. Type it into IDLE and run it to print the whole pattern, including the answer.

number = 45
for step in range(7):
    print(number)
    number = number - 4

When you run it, Python prints:

45
41
37
33
29
25
21