Question

Question 9 Every day when commuting to and from work, Stefanie drives her car a total of 143 miles for 2.5 hours. Her car already has 45,300 miles on it. a. Write a function that shows the total number of miles, f(x), Stefanie's car will have been driven after x more days. Explain how you know where each number goes in the equation. b. If Stefanie works 4 days a week, how many miles will her car have been driven after 3 weeks? Show and explain all your work.

Answer 1

First, determine the number of miles covered per day:

`\frac{143\text{ miles}}{2.5\text{ hours}}=57.2\text{ miles per day}`

Her car already has 45,300 miles on it.

(a)The total number of miles, f(x), Stefanie's car will have been driven after x more days will be:

`f(x)=45,300+57.2x`

(b) Stephanie works 4 days a week.

After 3 weeks, the number of days worked = 4 x 3 = 12 days

Therefore, when x=12:

`\begin{gathered} f(x)=45,300+57.2(12) \\ =45,300+686.4 \\ =45986.4\text{ miles} \end{gathered}`