Math Problem Statement

A linear function P is used to model the price, in dollars, of used cars as a function of their age, t, in years. It is known that P(4) = 7300 and P(7) = 5500. Based on this model, which of the following is true? (Options include decreases by 25%, 75%, $600, or $1800 per year.)

Solution

To determine the correct answer, let’s analyze the given problem step by step:

We know the following from the problem:

  • The price PP of a car is a linear function of its age tt.
  • P(4)=7300P(4) = 7300 and P(7)=5500P(7) = 5500.

Step 1: Find the rate of change (slope)

The rate of change (or slope mm) of a linear function is given by: m=ΔPΔt=P(7)P(4)74.m = \frac{\Delta P}{\Delta t} = \frac{P(7) - P(4)}{7 - 4}.

Substitute the known values: m=5500730074=18003=600.m = \frac{5500 - 7300}{7 - 4} = \frac{-1800}{3} = -600.

Thus, the price decreases by $600 per year.


Step 2: Interpret the result

The negative slope 600-600 means that for each additional year of age, the car's price decreases by approximately $600.


Step 3: Verify the options

  • Option A: Decreases by 25% → Incorrect (percentage not relevant here).
  • Option B: Decreases by 75% → Incorrect.
  • Option C: Decreases by approximately $600 → Correct.
  • Option D: Decreases by $1800 → Incorrect.

Final Answer:

The correct option is C: For each year that a car ages, its price decreases by approximately $600.


Do you want me to explain further or solve any related questions?

Here are 5 related questions to consider:

  1. How do you write the full equation of the linear function P(t)P(t) for this problem?
  2. If a car is 10 years old, what would its price be based on this model?
  3. How do you calculate the percentage decrease per year for this model?
  4. Can you verify the intercept of the linear function P(t)P(t)?
  5. What is the significance of the slope and y-intercept in this context?

Tip: Always check units and interpret the slope carefully when dealing with word problems involving linear functions.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Linear Functions
Slope
Rate of Change

Formulas

Slope formula: m = (P(t2) - P(t1)) / (t2 - t1)
Linear equation: P(t) = mt + b

Theorems

Properties of linear functions

Suitable Grade Level

Grades 9-10