I need help pls​

Acyclist bike x distance at 10 miles per hour .and returns over the same path at 8 miles per hour.what is the cyclist average rate for the round trip in miles per hour ?

Will give a: 122 b: 90 c: 48 d: 180

Marion has a bicycle that she is planning to take for a ride. the rim of the rear wheel lies 41 cm from the center of the wheel. the tire itself has a thickness of 3 cm. in order for marion to ride her bicycle 96,712 cm approximately how many rotations will the rear wheel make?