Please help with this

What could explain what happened when the time was equal to 120 minutes

Suppose i flip two identical coins. what is the probability that i get one head and one tail?

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.