What is the rate of change, I’m having some trouble figuring it out

For how answer my question this will be the last question can you answer in math subject

The average number of vehicles waiting in line to enter a parking lot can be modeled by the function f left parenthesis x right x squared over 2 left parenthesis 1 minus x right parenthesis endfraction , where x is a number between 0 and 1 known as the traffic intensity. find the rate of change of the number of vehicles waiting with respect to the traffic intensity for the intensities (a) xequals0.3 and (b) xequals0.6.

Linda loans her friend $250 with a 5% monthly intrest rate. how much was the whole loan?