The probability (as a percent) of scoring 3 or more on the Calculus AB Advanced Placement Examination can be very closely predicted as a function of a student’s PSAT/ NMSQT Score x by the function

P(x) = -0.00209x³ + 0.3387x² - 15.15x + 208.6.

Find the probability of scoring 3 or more for each of the following PSAT/NMSQT scores, as well as the rate that this probability is increasing with respect to the PSAT/ NMSQT score.
(i) 45

(ii) 75