Correct Answer - Option 2 : 50/3 km/h
Given
Speed for 45 km = 30 km/h
Speed for 30 km = 10 km/h
Formula used
Average speed = Total distance travelled/Total time taken
Time = Distance/Speed
Calculation
Time taken to travel 45 km at a speed of 30 km/h= 45/30
⇒ 1.5 hours
Time taken to travel 30 km at a speed of 10 km/h = 30/10
⇒ 3 hours
Total time taken = 1.5 + 3
⇒ 4.5 hours
Total distance travelled = 45 + 30
⇒ 75 km
Average speed = 75/4.5
⇒ 50/3 km/h
∴ Average speed is (50/3) km/h
