Declan can commute to Possum City by either fully automated (self-driving) bus or public access magnetized rail scooter. If he takes the bus in the morning, he comes home on the scooter in the afternoon; if he comes home in the afternoon on the bus, it means that he took the scooter that morning. Over the course of x days, Declan rode the bus 9 times and the scooter 8 times in the morning and 15 times in the afternoon. Find x.
Solution
This is far less complicated than it might seem. There is no need to work out when Declan did what. He took a total of 9 + 8 + 15 trips. That adds up to 32 trips, so x is 16 days. This is one of those fairly easy problems that are disguised as hard problems.
Note that the if-then statements in the problem seem to imply that Declan makes one bus trip and one scooter trip each day, but in fact, on many days he makes two scooter trips; he never makes two bus trips on the same day.