What is the meaning of each part of carl's expression

Acar travels at an average speed of 56 miles per hour. how long does it take to travel 196 miles

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

The wheels of a bicycle have a diameter of 70cm. how many meters will the bicycle travel if each wheel makes 50 revolutions