Question

37. Two trains of lengths 450 m ard 550 m 11.
are moving in the same direction with
speeds 50 km/h and 30 kn/h
respectively. Find the time taken by
them to cross each other.
(a) 3 minutes
(b) 5 minutes
(c)
4 minutes
(d) None of the above​

Answer 1

Given:

The length of 1st train = 450 m = $\frac{450}{1000}$ = 0.45 km

The length of 2nd train = 550 m =  $\frac{550}{1000}$ = 0.55 km

The speeds of the !st train and 2nd train moving in the same direction are 50 km/hr and 30 km/hr respectively.

To find:

The time taken by the trains to cross each other

Solution:

Let's assume,

"L1" = length of the 1st train

"L2" = length of the 2nd train

"S1" = speed of the 1st train

"S2" = speed of the 2nd train

∴ Total length = L1 + L2 = 0.45 + 0.55 = 1 km

Since the trains are moving in the same direction, so the relative speed of the two trains will be given by,

Relative Speed = S1 - S2 = 50 - 30 = 20 km/hr

Now, we will find the time taken by the trains to cross each other by the following formula,

$Time = \frac{Total \:Length}{Relative \:Speed}$

By substituting the values, we get

Time = $\frac{1}{20} \:hr = \frac{1}{20} * 60 \:minutes =$ 3 minutes ← option (a)

Thus, the time taken by the two trains to cross each other is 3 minutes.

--------------------------------------------------------------------------------------------------

Also View:

Two trains of length 200 m and 250 m respectively are running in opposite direction on parallel tracks. if their speed be 45 km per hour and 50 km per hour respectively, in what time will they cross each other?​

https://brainly.in/question/8215806

Two trains each of length 150 m are moving in opposite direction at 36 km/hr and 72 km/hr respectively. Time taken by them to just cross each other completely is?

https://brainly.in/question/10397020

Two trains of lengths 200 m and 250 m respectively are running in opposite directions on parallel tracks. If 119

their speeds be 45 km/h and 50 km/h respectively, in what time will they cross each other?

https://brainly.in/question/14536691

Answer 2

Given:

One train is 450m with speed 50 km/h

The other train is 550 m with speed 30 km/h

To Find:

The time needed for the train to cross each other

Solution

Find the total length of the two train:

Total length = 450 + 550

Total length = 1000 m

Find the difference in speed:

Difference = 50 - 30

Difference = 20 km/h

Difference = 20000 m/h

Find the time needed to cross each other:

Time needed = Distance ÷ Speed

Time needed = 1000 ÷ 20000

Time needed = 0.05 hour

Time needed = 3 mins

Answer: (a) 3 minutes