If x1 is the number of cars taking the ABD route and x2 is the number of cars taking the ACT route, write a linear expression for the travel time of a car taking the ABD route. Do the same for the ADD route.

The travel time for the car = Distance(Route-ABD)/Velocity of the car

t = d/v, where t is the travel time of the car, d is the distance traveled by the car along ABD, v is the velocity of the car.

For ADD route, ADD distance not mentioned in the question.

Notwithstanding, the travel time is given as :

t = Distance (ADD)/v

Step-by-step explanation:

The velocity is a physical quantity, which is defined as the rate of change of displacement with time.

That is, velocity = Displacement/time.

OR

Velocity(or speed) = Distance covered/traveled time.

The car is the question above traveled a distance(say d-meters) in the given route(ABD). It covered the distance in time, t(secs) with a velocity of v(m/s).

From the equation for velocity

v = d/t.

Making t the subject of formula,

travel time, t = d/v