A group of friends went on a trip by car. After 
of the regional road, they reached the highway, where they accelerated to a speed of 
.
Write down the function rule for calculating the total route on the regional road and highway.
Calculate how many kilometers they traveled in total after 
hours on the highway?
After 
hours of driving on the highway, they reached the exit and drove 
on the old road. How long did they drive on the old road if they reached their destination after 
from the start of their journey?
.
.
hours.
