Auto technicians working at a shop in a rural residential area noticed that the depth of tire treads was smaller among cars that have more miles on the odometer. What are the explanatory variable and response variable for this relationship?

Explanatory variable: type of residential area
Response variable: depth of tire tread
Explanatory variable: depth of tire tread
Response variable: miles on the car odometer
Explanatory variable: miles on the car odometer
Response variable: depth of tire tread
Explanatory variable: type of residential area
Response variable: miles on the car odometer

If p(x) is the total value of the production when there are x workers in a plant, then the average productivity of the workforce at the plant is a(x) = p(x) x . (a) find a'(x). a'(x) = xp'(x) − p(x) x a'(x) = xp'(x) − p(x) x2 a'(x) = p'(x) − p(x) x a'(x) = xp'(x) − p'(x) x2 a'(x) = p'(x) − xp(x) x2 why does the company want to hire more workers if a'(x) > 0? a'(x) > 0 ⇒ a(x) is ; that is, the average productivity as the size of the workforce increases. (b) if p'(x) is greater than the average productivity, which of the following must be true? p'(x) − xp(x) > 0 p'(x) − xp(x) < 0 xp'(x) − p'(x) > 0 xp'(x) − p(x) < 0 xp'(x) − p(x) > 0