Answer:
Explanation:
18 km / h
= 300 m / min
12 km / h = 200 m / min
distance travelled in 200 minutes = 300 x 200 = 60000 m
distance travelled in 50 minute in return journey = 200 x 50 = 10000 m
total distance travelled = 70000 m
total time = 250 minute
speed = 70000 / 250
= 280 m / min
= 16.8 km / h
Total displacement = 60000 - 10000 = 50000 m
total time = 250 min
velocity = 50000 / 250
= 200 m / min
= 12 km / h