Question

distance between Delhi to Agra is 200 kilometre the train travel the first hundred kilometre at the speed of 50 kilometre per hour how fast must the train travel the next hundred kilometres so as to the average of 70 kilometre​

Answer 1

time taken in first 100 km = 100/50 = 2hours

av. speed = 70 = (50+x)/2

x = 140 - 50 = 90km/hr