Question

On a 200 km track, a train travels the first 50 km
at a uniform speed of 40 km/h. How fast the train
must travel the next 150 km so as to maintain the
average speed of 60 km/h for the whole journey?
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Answer 1

Answer:

Explanation:

A =======B================C

Let AC is the length of railways track

e.g AC = 200 km

and AB = 50 km ,

Let speed of train for covered rest 150 km = P km/h

we know,

average speed = total distance /total time

Please mark as brainiest

total distance = 200 km

and averge speed = 60 km/h

total time = ?

total time = 200/60 hours = 10/3 hours

now,

time taken to cover first 50 km with 40 km/h = 50/40 = 5/4 hours .

so, time taken by train to cover next 150 km with P km/h = total time - time taken by train to cover first 50 km

= 10/3 - 5/4 = 25/12 hours

so, speed of train in next 150 km = 150/(25/12) = 150 × 12/25 = 72 km /h