### Home > PC > Chapter 9 > Lesson 9.3.4 > Problem 9-149

9-149.

Ryan’s sister Karen also has a toy car where the distance traveled in feet by the car is found by the equation *d* = 4*t*^{2}. What is the instantaneous rate of change of the car at 5 seconds? Homework Help ✎

Find the slope function and substitute *t* = 5:

IROC = 40 feet/second