Question

The Gordon family plans to buy a TV. One TV has a purchase price of $330 and an estimated yearly operating cost of $14. The other has a purchase price of $369 and an estimated yearly operating cost of $9. Which TV should the Gordons buy if they plan to keep it for 8 years? Use rational functions to help justify your answer.

ANSWER:rational functions that model the average annual cost of each television if it is owned for x years, such as f(x)= (330+14x)/x and
g(x)= (369+9x)/x

calculation proving that over 8 years, the annual cost for the $330 television is $55.25; for the $369 television, it is $55.13

statement that the Gordons should buy the $369 television because it is less expensive overall

step by step: edge 2023

Answer 1

The Gordon's should buy TV2

Explanation:

To determine which TV the Gordons should buy, we need to compare the total cost of each TV over the 8-year period. Let's define some variables:

- Let x be the number of years the TV is used.

- Let y1 be the total cost of TV 1 over x years.

- Let y2 be the total cost of TV 2 over x years.

- Let P1 be the purchase price of TV 1.

- Let P2 be the purchase price of TV 2.

- Let O1 be the annual operating cost of TV 1.

- Let O2 be the annual operating cost of TV 2.

Using these variables, we can write the following equations:

y1 = P1 + x * O1

y2 = P2 + x * O2

To compare the total cost of each TV over 8 years, we need to find y1 and y2 when x = 8. Plugging in the given values, we get:

y1 = 330 + 8 * 14 = 462

y2 = 369 + 8 * 9 = 441

Therefore, the total cost of TV 1 over 8 years is $462, and the total cost of TV 2 over 8 years is $441. Since TV 2 has the lower total cost, the Gordons should buy TV 2.

From a mathematical standpoint, we can also use rational functions to analyze this problem. The total cost of each TV is a linear function of x, so we can write:

y1(x) = P1 + x * O1

y2(x) = P2 + x * O2

The ratio of these functions is:

y1(x) / y2(x) = (P1 + x * O1) / (P2 + x * O2)

To determine which TV is cheaper over 8 years, we need to compare the ratios when x = 8:

y1(8) / y2(8) = (330 + 8 * 14) / (369 + 8 * 9) ≈ 1.051

Since this ratio is greater than 1, TV 1 is more expensive than TV 2 over 8 years. Therefore, the Gordons should buy TV 2.