Could someone help me and explain this problem to me?

Can someone me with this problem . show your work .

Which of the following tables represents exponential functions?

10 ! a train starts from grand city and travels toward belleville 388 miles away. at the same time, a train starts from belleville and runs at the rate of 47 miles per hour toward grand city. they pass each other 4 hours later. find the rate of the train from grand city.