An express train takes 2 hour less time than a passenger train to travel 400 km between two stations ( without taking into consideration the time they stop at intermediate stations ). If the average speed of the express train is 10 km/h more than that of the passenger train, find the average speed of the two trains

1

Answers

  • qais
  • Content Quality
2016-01-28T23:39:19+05:30

This Is a Certified Answer

×
Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Let the average speed of passenger train be v km/h
then, speed of express train will be (v+10) km/h
we know that, time = distance/speed
A/q,
400/v - 400/(v+10) = 2
⇒400(10) = 2(v(v+10))
⇒v² +10v -2000 =0
⇒v² +50v -40v -2000 =0
⇒v(v+50) -40(v +50) =0 
⇒(v+50)(v -40) = 0
⇒ v= 40 or -50
taking positive value,
average speed of passenger train will be 40 km/h
and the average speed of express train will be 50 km/h

0