It is given train X leave station A at 6:30 am, here it is asked to calculate the distance from A when the trains meet, the
Distance traveled by train left at 6:30 am upto 7:40 am i.e. in 1 hr. 10 min. or 7/6 hours = 30 x 7/6 = 35 km
So train leaving at 7:40 am will meet first train after covering a distance of 35 km. with relative speed of 40-30=10 km/hr.
Hence time taken = 35/10 = 3.5 hours or 3 hours 30 minutes
So distance from A = Distance traveled by 2nd train in 3 hr. 30 min
= 40 x 3.5 = 140 km.
Relative speed = 42 + 36 = 78 km/hr = m/s
Distance = (520 + 520) =1040 mts.
Time = = 48 sec
Let the length of the train be 'L' mts
let the speed of the train be 'S' m/s
Given it crosses a pole in 10 sec=> L/S = 10 ......(1)
Given it takes 20 sec (double of pole) to cross a platform of length 200 mts
=> (L + 200)/S = 20
=> L/S + 200/S = 20
But from (1) L/S = 10
=> 200/S = 20 - 10
=> S = 20 m/s
Then, from (1)
=> L = 10 x 20 = 200 mts.
Hence, the length of the train = 200 mts.
Let the speeds of the two trains be x m/sec and y m/sec respectively.
Then, length of the first train = 27 x meters, and
length of the second train = 17 y meters.
(27 x + 17 y) / (x + y) = 23
=> 27 x + 17 y = 23 x + 23 y
=> 4 x = 6 y
=> x/y = 3/2.
Speed of the Train K is given by s = d/t = 240/20 = 12 m/s
Distance covered by Train K in 50 seconds = 12 x 50 = 600 mts.
But it crosses Train L in 50 seconds
Therefore, the length of the Train L is = 600 - 240 = 360 mts.
Speed of the train relative to man = (125/10) m/sec = (25/2) m/sec.
[(25/2) x (18/5)] km/hr = 45 km/hr.
Let the speed of the train be 'S' km/hr.
Then, relative speed = (S - 5) km/hr.
S - 5 = 45 => S = 50 km/hr.
Speed of train relative to man = (60 + 6) km/hr = 66 km/hr.
[66*(5/18)] m/sec = (55/3) m/sec
Time taken to pass the man = [110*(3/55)]m/sec = 6 sec.
Given L1 = 140 m
L2 = 160 m
S1 = 60 km/hr
S2 = 80 km/hr
From the question we get,
S1 + S2 = (L1 + L2) / T
=> (60 + 80) 5/18 m/s = 140 + 160/T
=> T = 54/7 = 7.71 sec
Let the speed of the slower train = p kmph
ATQ,
Speed of the faster train = (p + 6) kmph
Then,
(p + p + 6) x 5 = 160
10p + 30 = 160
10p = 130
p = 13 kmph
Then, speed of the faster train = p + 6 = 13 + 6 = 19 kmph.
Birds speeds in mtrs/sec is 'x' and '2x' .
While flying from Engine to end, relative speed = (x+10) m/sec
from end to engine, flying speed = (2x - 10) mtr/sec
so
1000/(x+10) + 1000/(2x-10) = 187.5 secs
solving it, we get
so x = 8.728 m/sec and 2x= 17.456 m/sec
x = 31.4208 km/hr and 2x = 62.8416 km/hr.
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