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 km/h. Find the average speed of Rashid for the entire journey.
Answer & explanation
Correct answer: option 1
According to question ,
AB = BC = CA
LCM of ( 40 , 60 , 72 ) = 360
Let Distance = 360 km
Total distance = 360 + 360 + 360 = 1080 km
Time AB = \(\frac{360}{40}\) = 9 hours
Time BC = \(\frac{360}{60}\) = 6 hours
Time CA = \(\frac{360}{72}\) = 5 hours
Average speed = \(\frac{Total \; Distance }{Total \; Time }\)
= \(\frac{1080}{20}\)
= 54 km/h