Question

A man covers three equal distances first at the rate of 10 km/hr, second at the rate of 20 km/hr, and third at the rate of 30 km/hr. If he covers the third part of the journey in 2 hours. Find the average speed of the whole journey.

• A. 14.25 km/hr
• B. 25.25 km/hr
• C. 16.36 km/hr
• D. 60.50 km/hr

Answer 1

Answer:

C. 16.36 km/hr

Let the three distances be x km, x km, and x km. third part of the journey is covered in 2 hours ⇒ x/30 = 2 hrs ⇒ x = 60 km Total distance = (60 + 60 + 60)km = 180 km Total time = 60/10 + 60/20 + 60/ 30 = 11 hrs Average speed = 180/11 km/ hr ⇒ 16.36 km/hr