Quadratic is a type of problem which deals with a variable multiplied by itself- an operation also known as squaring.
Solution:
Let’s consider the speed of the fast train as x km/hr
Then, the speed of the slow train will be km/hr
Using, speed = distance/ time
Time taken by the fast train to cover km
hr
And, time taken by the slow train to cover km
hr
Given, that the difference in the times is hour.
This can be expressed as below:
[by factorisation method]
As, the speed of train can never be negative we neglect
Thus, speed of the fast train is km/hr
And the speed of slow train km/hr