Question

The distance between Akola and Bhusawal is 168km.An express train takes 1hour less than a passenger train to cover the distance. Find the average speed of each train ir average speed of express train is more by 14km/hr than the speed of passenger train​

Answer 1

The average speed of passenger train = 42 km/hr

The average speed of express train = 56 km/hr

Step-by-step explanation:

Given,

The distance between Akola and Bhusawal is = 168 km

Consider the average speed of passenger train = (x) km/hr

Consider the average speed of express train = (x+14) km/hr

we know that

The time take by the passenger train to reach the distance =

The time take by the express train to reach the distance =

As per problem ..................equation 1

For Quadratic Equation

the value of

when Discriminant (D) is positive, we get two Real solutions  for x

when Discriminant (D) is zero we get just ONE real solution (both answers are the same)

when Discriminant (D) is negative we get a pair of Complex solutions

In equation 1 the Discriminant (D) is =

As the Discriminant (D) is positive, we get two Real solutions  for x

therefore the value of x is either

or,

As speed is not consider as a negative value so we take the positive value of x=42

therefore,

The average speed of passenger train = 42 km/hr

The average speed of express train = (42+14)=56 km/hr