A. 1 hr
B. $$1{1} / {7}$$
C. $$1{1} / {2}$$
D. 2 hrs
Two trains are coming from opposite directions with speeds of 75 km/hr and 100 km/hr on two parallel tracks. At some moment the distance between them is 100 km. After T hours, distance between them is again 100 km. T is equal to
Two trains are coming from opposite directions with speeds of 75 km/hr and 100 km/hr on two parallel tracks. At some moment the distance between them is 100 km. After T hours, distance between them is again 100 km. T is equal to
A. 1 hr
B. $$1{1} / {7}$$
C. $$1{1} / {2}$$
D. 2 hrs
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1(1/7)hr
First we need the length of the train.
S=100km+100km=200km
V= 75+100= 175
t=s/v, 200/175 , 8/7= 1/(1/7)
Trains speed = (75 + 100)km/hr = 175 km/hr
How much time it took to cover 175 kmat
Trains speed = 1 hr∴T =
How much time it took to cover 200 km = (1175×200)hr=87hr=117hr
So the answer id (B).
Here length of the train =100+100=200km
Then
Gn
Trains are in opposite direction :
So speed=s1+s2
. =75+100=175km/hr
Time T=D/S
=200/175
=8/7
=1(1/7) hr
Yes good