Write a word problem that can be solved by finding the numbers that have 4 as a factor

The numbers that have 4 as a factor are numbers that are divisible exactly by 4. A word problem may be outlined as followed: If 100 people are lined up in a queue to a cash machine, list the numbers that occur every 4 people. In this case the answer is 4,8,12,16,20,24,28 and a further every 4 up to 100.