Riddle Me This

At the beginning of the semester, 2 of my senior students told me that they had class with one of the other foreign teachers. I was suprised by this because the foreign teacher, Jenny from England, doesn’t teach any of the english majors. In fact, she mostly teaches children.
But it turns out it was a special IELTS (an English language test you need to go abroad) class. I ran into one of my students on the way to Jenny’s class and I said “Tell Jenny I say hi!”
But then I paused. “Hi” is so….well, generic, boring. I wanted my students to say more than just hi from me. So I started thinking what would be funny. A tongue twister? A joke? How about a riddle?
So I contacted Jenny and asked her how she felt about passing riddles back and forth. She would see these 2 students on monday, I would see them on Thursday. We could give them a piece of paper with a new riddle on it, and the students could pass it back and forth.
Turns out Jenny not only enjoys riddles, but is really good at them. So we started a weekly tradition.
The two students ended up getting really into them too. Sometimes they couldn’t even wait the few days for my class, but would text me with the riddle the same day Jenny told them. Other times Jenny gave them 2 riddles, one for me and one for them, and they would text me and ask for my help. Once, one student got into it and asked me and Jenny her own riddle!
I’m no riddle master, so I would often get the whole class involved. If I couldn’t figure it out quickly, I would ask my whole class and we would spend a few minutes thinking of the answer together. Sometimes, when I really couldn’t get it, I would ask the students passing them back and forth, since they almost always knew the answers from either Jenny or I.

It turned out to be a fun little game between the 4 of us. The students are  from my favorite classes and I love how willing they are to try new things, and have some fun.
Here are some of the riddles we passed back and forth. Can you figure them out?
 
When I am young, I am tall. When I am old, I am short. What am I? 
 
What has cities but no buildings, forests but no trees, roads but no cars? 
 
Poor people have it. Rich people need it. If you eat it, you die. What is it?  
 
You’re a bus driver. The bus starts in yorkshire, and picks up 3 people. At the next stop 5 people get on, 2 get off. At the next stop 10 people get on, while only 3 get off. The next stop 2 get on, 4 get off and at the last stop in marblehead, every disembarks. Where is the drivers hometown?