A motorist travels to a place 150 km away at an average speed of 50 km and returns at 30 km per hour. What is his average speed for the whole journey in km per hour?
সমাধান
সঠিক উত্তর: Option C
We know that, Speed = Distance/Time taken
Thus, Time taken = Distance/Speed
While Travelling,
Time taken = 150/50 = 3 hours
While Returning,
Time taken = 150/30 = 5 hours
Total time taken during the journey = 3 + 5 hours = 8 hours
And, Total distance covered during the journey
= (150 + 150) km
= 300 km
Thus Speed = 300/8 = 37.5 km/h
