A car travels 40 kilometers at an average speed of 80km/h and then travels 40 kilometres at an average speed of 40km/h; The average speed of the car for this 80-km trip is:
Correct answer: D. 53 km/hr
- A. 40 km/hr
- B. 45 km/hr
- C. 48 km/hr
- D. 53 km/hr
Explanation
Calculating Average Speed for the TripGiven:1. 40 kilometers at 80km/h2. Another 40 kilometers at 40km/hCalculating Total Time Taken:For the first 40kilometers at 80km/h:Time1 = Distance1/Speed1 = 40km/80km/h = ½ hourFor the next 40 kilometers at 40 km/h:Time2= Distance2/Speed2 = 40km/40km/h = 1 hourTotal Distance Travelled:Total Distance =40km+80km=120kmTotal Time Taken:Total Time = Time1 + Time2 = ½ hour+1hour = 3/2 hoursAverage Speed for the Entire Trip:Average Speed = {Total Distance}/{Total Time}= 80 km/ (3/2) hours}= 160/3 km/h} = approximately 53.33 km/hThe calculated average speed for the entire 80-km trip is approximately 53.33 km/hr, which aligns closest with option (D).
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