John attends a protest for 4 days. He then attends a second protest for 25% longer than the first. How many days did he spend protesting? Let's think first. Chain of thought:
The second protest was 4 * .25 = 1 day longer than the first. So the second protest was 4 + 1 = 5 days. Thus he spent 4 + 5 = 9 days protesting.
Therefore, the answer is 9.