Kerri drives 150 miles to visit her grandmother. she starts off driving 60 miles per hour, but then encounters road construction and has to drive 20 miles per hour the rest of the way. if she spends the same amount of time at the faster speed as at the slower speed, then how many hours did her 150-mile trip take in total?

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,