A car rental company charges a flat fee of ₱500 plus ₱25 per kilometer driven. Which rational function represents the cost per kilometer C of renting the car if you drive x kilometers?

A water tank is being filled at a rate of 10liters per minute. The volume V of water in the tank after t minutes is represented by the function V(t)=100+10t, where 100 liters was the initial amount. What will V(t) be after 20 minutes?

A construction company’s cost function C(x)= +500 represents the total cost (in pesos) of constructing x identical units. If the cost per unit decreases as x increases, what does this imply about the relationship between x and the average cost per unit?

The function P(d)= models the population density (in people per square kilometer) of a region as a function of distance d from the city center. If the function is evaluated at increasing values of d, what can be inferred about population density?

The function S(h)= models the speed S (in liters per minute) of a filtration system in relation to hours h since it began operating. What does this function suggest about the system's speed as more hours pass?