Three cities, A, B, and C are located such that they form the vertices of an equilateral triangle if joined by straight lines. Rashid travels from A to B at the speed of 40 km/h, from B to C at the speed of 60 km/h and from C to A at the speed of 72 k /h. Find the average speed of Rashid for the entire journey.
Explanation:
Let the sides of the equilaterl triangle be 360 kms each.
Time taken to travel from A to B = 360/40 = 9 hours Time taken to travel from B to C = 360/60 = 6 hours Time taken to travel from C to A = 360/72 = 5 hours
∴ Total time taken = 9 + 6 + 5 = 20 hours to travel a total of 360 + 360 + 360 = 1080 kms.
∴ Average speed = 1080/20 = 54 kmph.
Hence option (a).