A bicyclist rides the first 60 km of a 220 km race in 1.5 hours. What is the bicyclist average speed? I know that the answer is 7.5,  however I'm trying to establish a formula for solving problems such as this one. Is there a formula that you can provide to solve problems that require calculating miles per hour based on only feet and seconds?

A Porsche challenges a Honda to a 400-mm race. Because the Porsche's acceleration of 3.5 m/s2m/s2 is larger than the Honda's 3.0 m/s2m/s2, the Honda gets a 1.0 ss head start. By how many seconds? Express your answer in seconds to two significant figures.

Evan is just leaving his house to visit his grandmother. Normally, the trip takes him 25 minutes on the freeway, going 55 mph. But tonight he’s running 5 minutes late. How fast will he need to drive on the freeway to make up the 5 minutes?

Professor Wells (from the Computer Science department) is going to ride the Argus CycleRace in Cape Town this weekend. The race is 108 km long.(a) Prof. Wells is comfortable riding at an average speed of 25 km/h, but he would like to ride the race in under 4 hours. What average speed will he need  to ride in order tofinish the race in 4 hours?(b) During the race, Prof. Wells finds that he rides down a 15 km long hill at an average (9)speed of 45 km/h. This downhill is followed immediately by a 15 km long uphill ride.With what average speed will Prof. Wells need to ride up the hill to maintain anaverage speed of 30 km/h over the 30 km stretch of road?