Problem 19

Given information

The given information is 

In an automobile race along a straight road, car A passes car B twice.

Step-by-step explanation

Let and be the position functions of cars A and B respectively.

Let  

Since it is given that A passes B twice, therefore there must exist at least three times when their positions are equal.

Let be the time when A overtakes B the first time.

is the time when B overtakes A, and 

is the time when A again overtakes B.

 So, the position of cars at time and is,