Word Problem

Question

The value of each truck that a delivery company owns is a linear function of the age of the truck. If a truck that is one year old is worth $13,750 and a truck that is 7 years old is worth $6,250, what is the value of a truck that is three years old?

Answer 1

The information given can be viewed as two points on the line of straight line depreciation.

 

That is, points (1, 13750) and (7, 6250) are two points on a line.

So you can calculate the slope (it's negative), and can use point slope form y-y₁ = m(x-x₁) to obtain the equation, choosing either of the above specific points as P₁.

 

Finally, substitute x=3 and calculate y.