yeah, i know people will tell me to do it myself and stop being lazy but i just can't figure it out! it's my last graduation requirement.

A large wildlife park is circular in shape and has a diameter of 7 miles.

Around the outskirts of the park is a circular train track. Two automatic trains travel around the park, both in a clockwise direction. The trains are designed to both average 20 mph so that they never meet. However, one train has developed a fault and now travels at 18 mph.

The trains set off from stations on opposite sides of the park at 9 a.m. At what time will the faster train catch up with the slower train?

and it asks these questions as well:

Where will the trains be when one catches up with the other?

How many times will each train pass its starting point before they meet?

When the faster train has caught up with the slower train, it changes direction. both trains are now traveling in opposite directions. After how many minutes will the trains meet again?

i am not asking for people to do it and give me the answers..i just really need help with this. it also says:

circumference = π x diameter. use π = 22/7

thank you!