Question

The distance between Delhi and Agra is 200km a train travels the first 100km at a speed of 50km/h how fast must the train travel the next 100km so as to average 70 km/h to the whole journey

Answer 1

●ACCORDING TO QUESTION :-

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

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Now

» Time required to maintain an average speed of 70 km/hr = Distance/speed = 200/70 = 20/7 hour

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Now

» Time remaining = 20/7 - 2 = 6/7 hours

» Remaining Distance = 100 km

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» Speed = Distance/time

» Speed = 100/(6/7)

» Speed = 700/6 km/hr

» Speed = 350/3 km/hr
-_______________[ANSWER]

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_-_-_-_✌☆$BE \: \: \: \: BRAINLY$☆✌_-_-_-_

Answer 2

$\red{HEY\:BUDDY!!}$

HERE'S THE ANSWER..

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♠️ First we'll find time taken in covering 100 Km with the speed of 50 Km / h

⏺️ We know

✔️ Speed = Distance / Time

=> Time = Distance / Speed

=> Time = 100 / 50

=> [ Time = 2 Hour ]

♠️ Now time taken in covering next 100 Km with the speed ( v )

=> Time = Distance / speed

=> Time = ( 100 / v ) Hour

♠️ Now average speed is ratio of total distance traveled to the total time taken

⏺️ Total distance = 100 + 100 = 200 Km

⏺️Total time = [ 2 + ( 100 / v ) ] Hour

⏺️ Average speed = 70 Km / hour

▶️ Now putting value in formula

♠️ Avg Speed = total distance traveled / Total time taken

✔️ To make it more clear Calculation is in attachment ..

♠️ So the Speed required to get the average speed of 70 Km / h is ( v )

=> $\boxed{v \:= \: 350/3 \: \:Km/h}$

HOPE HELPED..

$\red{JAI \:HIND..}$

:)