A train sets off at 3 p.m. at the speed of 70 kmph. Another train starts at 4:30 p.m. in the same direction at the rate of 85 kmph. At what time the trains will meet ?

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: 36 sec

Correct Answer: 400

Correct Answer: 500

Correct Answer: 30 kmph

Explanation:

Let the speed of the faster train be 'S' kmph

 

Then speed of the slower train will be '(S-5)' kmph

 

Time taken by faster train = 350/S hrs

 

Time taken by slower train = 350/(S-5) hrs

  350 s - 5 - 350 s = 2 h r s 20 m i n = 2 1 3 = 7 3

 

=> S = 30 km/hr.

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: 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: 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: 3 : 2

Explanation:

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.

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.