Question

From point A located on a highway (Fig. 1.2) one has to get by car as soon as possible to point B located in the field at a distance l from the highway. It is known that the car moves in the field η times slower than on the highway. At what distance from point D one must turn off the highway?

Answer 1

Let the car turn off the highway at a distance x from the point D.

 So, CD=x and if the speed of the car in the field is v, then the time taken by the car to cover the distance AC=AD-x on the highway