Hint
It doesn't matter what the distance is, so try a random distance.
Answer
This cannot be done.
It does not matter how far the trip is, let's assume that it is random distance, say 60 miles, and remembering that Time = Distance ÷ Speed.
The morning trip took 60 miles ÷ 30 mph = 2 hours.
To average the required 60 mph, we would have to travel the total distance (of 120 miles) in 2 hours. However, we've already used all of the two hours for the morning trip!
Choosing any random distance would also show that it can't be done.
Alex's child, Drew, is exactly one fifth of Alex's age. In 21 years, Alex will be exactly twice Drew's age. How old is Drew now? Billie is exactly seven times the age of his child, Glen. In 8 years, Billie will be three times the age of Glen. How old is Glen now?