Answer:
i) 30 minutes
ii) 50 km/h
Explanation:
Part 1:
1540 - 1600 is pnt 1 to pnt 2; 1 km per hour. (20 minutes)
15km at 90km/h = 10 min
20 + 10 = 30 minutes
Part 2:
10 km/h + 90 km/h = 100km/h
Average = /by number of factors;
100 km/h / 2 = 50 km/h (Average journey speed)