An empty bus pulls up to a stop and 10 people get on. At the next stop 5 people get off and twice as many people get on as at the first stop. At the third stop 25 get off. How many people are on the bus at this point?

Why this works

This riddle plays with our expectations about counting passengers. Initially, we might think to tally the number of people getting on and off the bus, but the key detail is that the bus starts empty and we only account for the passengers getting on and off. After the first stop, 10 people board, followed by 5 disembarking and 20 getting on at the next stop, leading to a temporary total of 25 on the bus. However, at the third stop, 25 people get off, leaving us with just the bus driver still on the bus. The twist is in realizing that while the numbers seem to suggest a full bus, the phrasing ultimately leads us back to the lone driver.