a car travels 30 km at a uniform speed of 40 kilometre per hour and the next 30 kilometre at the uniform speed of 20 kilometre per hour find its average speed
Answers
Answer:
Average speed = 26.66 Km/hr
Explanation:
Uniform speed in 1st 30 Km (u¹) = 40 Km/h
Uniform speed in 2nd 30 Km (u²) = 20 Km/hr
Time taken to travel 1st 30Km (t¹) = d/u¹
= (30/40)*60
= 3*15 = 45 min
Time taken to travel 2nd 30Km (t²) = (30/20)*60
= 3*30 = 90 min
Total distance = (30 + 30) Km = 60 Km
Total time = (45 + 90)/60 = 135/60
We know that ,
Average speed = Total distance/Total time
= 60/(135/60) Km/hr
= 60*60/135 Km/hr
= 26.66 Km/hr