Question

on a 120km track a trian travels the first 30km at a uniform speed of 30k/h . How much fast must be travel the next 90km so as to average 60km/h for the entire track ​

Answer 1

Answer:

90 km

Explanation:

as the total distance 120 km average speed = 60 kmph => total time duration=120/60 = 2

hours

time taken for the first 30 km = 30 km / 30 kmph = 1 hours

Hence, time remaining to cover the remaining 90 km = 2 hrs - 1 hrs = 1 hour => speed during 90 km = 90 kmph

Answer 2

Answer:

Explanation:

Track Length= 120km

He travels first 30km with 30 kmph

Required time = 1 hour

Now to get average speed of 60kmph he should cover track of 120 km in (120/60) = 2 hours

But he traveled only 30 km in 1 hour

So to attain average speed of 60 kmph he must travel by (120-30)/(2-1) = 90 kmph

He he should travel 60km fast to achieve its target