Question

Question 1(Multiple Choice Worth 1 points)

(02.04 LC)
A student is running a 3-kilometer race. He runs 1 kilometer every 2 minutes, Select the function that
describes his distance from the finish line after x minutes.
f(x)=-1/3x+2
f(x)=-1/2x+3
f(x)=1/2x+3
f(x)=1/3x+2

Answer 1

f(x)=-1/2x+3

Explanation:

In this problem, the student is running a 3-kilometer race.

This means that the total length of the race is 3 km.

We also know that the student runs 1 kilometer every 2 minutes. For a uniform motion, the speed is given by

`v=(d)/(t)`

where in this case,

d = 1 km is the distance

t = 2 min is the time

So the speed is

`v=(1)/(2)`

We can therefore write the distance covered by the student (from the starting line) after x minutes as

`y'=(1)/(2)x`

However, here we want to write an expression for the distance of the student from the finish line.

Since the distance from the finish line at x = 0 is 3, therefore the distance from the finish line after x minutes is:

d = 3 - y'

So

`y=3-(1)/(2)x`

which corresponds to the option:

f(x)=-1/2x+3