Question

Two trains left Delhi to agra at an interval of 10 minutes and each with a speed of 30km/hr . What was the speed of a third train moving towards Delhi if it met these two trains at an interval of 4 minutes ??
A.) 30km/hr
B.) 45km/hr
C.) 15km/hr
D.) 20km/hr

Answer 1

Explanation:

HEY MATE

here is your answer 45 km/hr

:)

Answer 2

Answer:

45 km/hr

B is correct.

Explanation:

Given Problem:

Two trains left Delhi to agra at an interval of 10 minutes and each with a speed of 30km/hr . What was the speed of a third train moving towards Delhi if it met these two trains at an interval of 4 minutes ??

A) 30km/hr

B) 45km/hr  

C) 15km/hr

D) 20km/hr

Solution:

Two trains left Delhi to Agra at an interval of 10 minutes and each with a speed of 30 km/hr.  

First we find the distance of two train leave from Delhi to Agra:

We know that:

$Distance = Speed * Time$

Distance of two trains = $30*\frac{4}{60} = 5km$

Now,

If third train met these two trains at an interval of 4 minutes.

This 5 km distance covered in 4 minutes.

One train running towards third train.

Relative velocity of two train.

Let speed of third train be s

30 + s = $\frac{5}{4} *60$

30+s = 75

s = 45km/h

Hence,

The velocity of third train is 45 km/h