For a certain model of car the distance d required to stop the vehicle if it is traveling at v mi/h is given by the formula d = v + v2/20
where d is measured in feet. Kerry wants her stopping distance not to exceed 120 ft. At what range of speeds (in mi/h) can she travel? (Enter your answer using interval notation.)

correct choice is b

step-by-step explanation:

when you calculate the average rate of change of a function, you are finding the slope of the secant line between the two points. for the function the average rate of change from point to point can be calculated as

to find the average rate of change from day 2 to day 10, note that at day 2, 8 houses were sold, so a(2,8) and at day 10, 2 houses were sold, so b(10,2). thus,

answer: it depends on what the tax percentage