On a 60km track travels the first 30km with a uniform speed of 30km/h. How fast must the train travel the next 30km so as to average 40km.h for the entire trip?
(a) 60km.h
(b) 90km/h
(c) 120km/h
(d) 30km/h
I had been asked this question by my college professor while I was bunking the class.
This interesting question is from Motion and Mechanics in division Advanced Engineering Materials of Engineering Physics II