# A man complete a journey in 10 hours. He travels first half of the journey at the..........Find the total journey in km.

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A man complete a journey in 10 hours. He travels first half of the journey at the rate of 21 km/hr and second half at the rate of 24 km/hr. Find the total journey in km.

posted Jan 6, 2016

Let's total time=t=10 hrs= 600 min............(i)
total distance travelled=x
half distance=d1=d2=x/2........................................(ii)
Speed=s1=21 km/hr= 0.35 km/min..............................(iii)
s2= 24 km/hr= 0.4 km/min.................................(iv)
t=d/s=[(d1/s1)]+[(d2/s2)]
600 = [( x/2) / 0.35] + [( x/2) / 0.4]
600 = x/2* [ 2.857 + 2.5 ]
x = 600*2 / 5.357
x = 224 km

t=d/s=[d1/s1]+[d2/s2]
10*60=[(x/2)/(21/60)]+[(x/2)/(24/60)]..............convert hrs in min
x=1600km
ans is total journey 1600km

plz check it once
as speed is given   21 and 24 in 1 hr
then min distance it will cover in 10hr will be 210 km
and max 240 km .  How it will be 1600 km??

let x is total distance
(1/2)*x/21 + (1/2)*x/24 = 10
x/21+ x/24 = 20
15x = 168*20
x =(168*20)/15= 224 km.

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