How to solve this problem

Question

A group of bikers from LA took 4-hour trip. For the first 3 hours, they traveled a total of 50 km, but during the last hour, they traveled only 10 km. What was the group's average speed for the entire trip?

Answer 1

The total time of travel= 3+1=4 hrs

The total distance traveled in 4 hrs = 50+10=60 km

Therefore their avg speed= (60/4) km/hr=15 km/hr