Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is ?

Correct Answer: 360 mts

Explanation:

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.

Correct Answer: Option A

Explanation:

As Trains are moving in same direction,

Relative Speed = 60-20 = 40 kmph

-->  40 × 5 18 = 100 9 m/sec

 

Length of Train= Speed * Time

 

Length =  100 9 × 6

$$\begin{gathered} ? 200 3 = 66 2 3 m t s \\ \end{gathered}$$ 

Correct Answer: 100 mts

Explanation:

We know that    S p e e d = d i s tan c e t i m e 

distance= speed * time

?  d = 40 × 5 18 × 9

   d= 100 mts.

Correct Answer: 11:30 pm

Explanation:

Distance = 70 x 1 ½ = 105 km

Relative Speed = 85 ? 70 = 15

Time = 105/15 = 7 hrs

4:30 + 7 hrs = 11.30 p.m.

Correct Answer: 355 mts

Explanation:

Given speed = 63 km/hr =  63 × 5 18 = 35 2 m/s

Let the length of the bridge = x mts

Given time taken to cover the distance of (170 + x)mts is 30 sec.

We know speed =  d i s tan c e t i m em/s

? 35 2 = 170 + x 30

 -->  x = 355 mts.

Correct Answer: 200 mts

Explanation:

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.

Correct Answer: 27 7/9 mts

Correct Answer: 48 sec

Explanation:

Relative speed = 42 + 36 = 78 km/hr = 65 3 m/s

Distance = (520 + 520) =1040 mts.

Time =  1040 × 3 65= 48 sec

Correct Answer: 140 kms

Explanation:

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.

Correct Answer: 50 kmph

Explanation:

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.