Navjivan Express from Ahmedabad to Chennai leaves Ahmedabad at 6:30 am and travels at 50kmph towards Baroda situated 100 km away. At 7.00 am Howrah-Ahmedabad Express leaves Baroda towards Ahmedabad and travels at 40 kmph. At 7:30 am Mr. Shah, the traffic controller at Baroda realizes that both trains are running on the same track. How much time does he have to avert a head-on collision between the two trains?

Navjivan Express from Ahmedabad to Chennai leaves Ahmedabad at 6:30 am and travels at 50kmph towards Baroda situated 100 km away. At 7.00 am Howrah-Ahmedabad Express leaves Baroda towards Ahmedabad and travels at 40 kmph. At 7:30 am Mr. Shah, the traffic controller at Baroda realizes that both trains are running on the same track. How much time does he have to avert a head-on collision between the two trains? Correct Answer 15 min

Given: 

Navjivan Express from Ahmedabad to Chennai leaves Ahmedabad at 6:30 am and travels at 50km/h towards Baroda 

At 7.00 am Howrah-Ahmedabad Express leaves Baroda towards Ahmedabad and travels at 40 km/h

At 7:30 am Mr. Shah, the traffic controller at Baroda realizes that both trains are running on the same track

The distance between Ahmedabad to Baroda is 100 km.

Concept: 

Time = Distance/Speed

Calculation: 

At 7.30 AM, Distance travel by Navijan express is 

⇒ 50 × 1

⇒ 50 km

At 7.30 AM, Distance travel by Howrah-Ahmedabad Express is 

⇒ 40 × 1/2

⇒ 20 km

Now, Distance left between the both train is 

⇒ 100 - 50 - 20

⇒ 30 km

Both train travel in opposite direction, then relative speed of the trains is 

⇒ 50 + 40

⇒ 90 km/h

Time taken to cover this distance by both train is 

⇒ 30/90

⇒ 1/3 hour = 20 min

So, He have to time less than 20 min to avert the head on collision between two trains.

∴ 15 min

Related Questions

The question below is followed by two statements I and II. You have to determine whether the data given is sufficient for answering the question. You should use the data and your knowledge of mathematics to choose the best possible answer. Train A departs at 9 : 20 am and train B departs at 10 : 50 am and they travel towards each other. After how much amount of time will the trains meet? I) Train A travels with a speed of 10 kmph and the difference between the speed of two trains is 6 kmph and both the trains are 160 km apart. II) Train B travels at a speed greater than Train A which travels with 10 kmph by 6kmph separated by a distance of 160 km.