Question

Need help with this one it kind of hard

Answer 1

The answer is D because the question is basically asking you to solve for the equation at t = 5. We get:
$v(5) = 45+4(5) = 65$

Since it models speed of the car, and not the time, the answer is D.

Answer 2

we have

$v(t)=35+4t$

where

v(t) is the speed of the car in mph

t is the time in seconds

the domain of the function is the interval ------> $[35,55]$ (given problem)

so

V(5) -----> that means the speed of the car for the time equal to $5$ seconds

Find the speed of the car for $t=5\ sec$

substitute the value of t in the formula above

$v(5)=35+4*5$

$v(5)=55 mph$

therefore

the answer is the option D

$55 mph$