Gopal travels from A to B at the speed of 5km/h, from B to C at 10 km/h, and from C to D at 15 km/h. If AB = BC = CD, then find Gopal’s average speed.

$8\frac{2}{11}$ km/h

According to question ,

AB = BC = CA

LCM of ( 5 , 10 , 15 ) = 30

Let Distance = 30 km

Total distance = 30 + 30 + 30 = 120 km

Time AB = \(\frac{30}{5}\) = 6 hours

Time BC = \(\frac{30}{10}\) = 3 hours

Time CA = \(\frac{30}{15}\) = 2 hours

Average speed = \(\frac{Total \; Distance }{Total \; Time }\)

= \(\frac{90}{11}\)

=  8\(\frac{2}{11}\) km/h