On a 60km track, a train travels the first 30km with a speed of 30kmh−1 . How fast must the train travel the next 30km so as to average 40kmh−1 for the whole trip? - Padhle.Online
Students' favourite free learning app with LIVE online classes, instant doubt resolution, unlimited practice for classes 6-12, personalized study app for Maths, Science, Social Studies, video e-learning, online tutorial, and more. Download Now!

On a 60km track, a train travels the first 30km with a speed of 30kmh−1 . How fast must the train travel the next 30km so as to average 40kmh−1 for the whole trip?

 It is given that the first 30km is traveled with the speed 30kmh−1 , let us consider that the speed with which the next 30km is travelled be xkmh−1

Now as we know that time=distance/speed

This implies the time t1 taken to travel the first 30km will be

t1 = 30km/30kmh−1 = 1h

The time taken to travel the next 30km will be

t2=30km/xkmh−1 = 30/x h

Now as the average speed for the whole trip is 40kmh−1 , so, average time taken for whole trip is

t = 60km/40kmh−1 = 3/2h

This implies 1h+30/x h = 3/2h

Further solving for the value of x ,

we get ⇒ 30/x = 1/2

⇒ x = 60 Thus, the train travels the next 30km with the speed 60kmh−1

About the Author

Principal, Babu Daudayal SVM, Mathura

Post a Comment

Cookie Consent
We serve cookies on this site to analyze traffic, remember your preferences, and optimize your experience.
Oops!
It seems there is something wrong with your internet connection. Please connect to the internet and start browsing again.
AdBlock Detected!
We have detected that you are using adblocking plugin in your browser.
The revenue we earn by the advertisements is used to manage this website, we request you to whitelist our website in your adblocking plugin.
Site is Blocked
Sorry! This site is not available in your country.