Question

A student is running a 5-kilometer race. He runs 1 kilometer every 3 minutes. Select the function that describes his distance from the finish line after x minutes.

f(x) = − 1/3x +5

f(x) = − 1/5x + 3

f(x) = 1/5x + 5

f(x) = 1/3x + 3


Plz explain

Answer 1

Answer: A, f(x)=-1/3x+5

Answer 2

Answer: A. f(x) = − 1/3x +5

A student is running a 5-kilometer race, the total distance is 5 km.

He runs 1 kilometer every 3 minutes.

So the speed will be,

Speed = Distance/time

Speed = 1/3

Speed is the rate of change or slope and as the total distance is decreasing with time so it will in negative, thus;

Slope = -1/3

So when on x axis time and y axis distance is represented, 5 will be the y intercept.

Then put all the values in slope intercept form of straight line,

y = mx + c

y = -1/3x + 5

y = 5 -1/3x