Question

(a) distance between delhi and agra is 200km. atrain travels thefirst 100km at the speed of 50km/h. how fast must the train travel next 100 km so as to average 70km/h for the whole journey?

(b) ona 120 km track, a train travel the first 30 km at speed of 30 km/h how fast must the train travel the next 90km so as to average 60km/h​

Answer 1

Answer:

Time taken to travel first half distance = 100/ 50 = 2 hrs

Time is taken to travel second half distance = 100/v

Average speed = 200/ (2 + 100/v)

70 = 200/ (2 + 100/v)

2 + 100/v = 20/7

100/v = 20/7 – 2 = 6/7

v = 100 * 7/6 Km/h

v = 700/6 km/h

Step-by-step explanation:

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