Question

on a 120 km track a train Moves the first 30 km at uniform speed of 30 km per hour how fast does the train travel in the next 90 km so as to have average speed of 60 km per hour for the entire trip

Answer 1

Hey

Speed of the train in the first 30 km, v1 = 30 km/h
Speed of the train in the next 90 km, v2 (to be determined)
Average speed = 60 km/h = (v1 + v2)/2 
                                          = (30 km/h + v2)/2 

⇒ v2 = 90 km/h


Hope it helps to you.

Answer 2

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һєяє' ʏȏȗя ѧṅśwєя ʟȏȏҡıṅɢ ғȏя________
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✪ distance d1 = 30 km

✪v1 = 30 kmph

✪time taken (t1) = d1 / v1 = 1 hour.

so, distance remaining = d2 = 120 - d1 = 90 km .

✪lets speed to cover distance d2 = v2 kmph

=》 time taken = d2 / v2 = 90 /v2 hours.

✪average speed = total distance / total duration of time

60 kmph = 120km / [ 1 hour + 90 /v2 hours]

=》 1= 2 / [ 1 + 90 /v2 ]

✪=》v2 =》 90 kmph


$hope \: it \: helps$

✪BRAINLY✪


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