In learning theory, receptivity is defined as the ability of students to understand a complex concept. Receptivity

Question:

In learning theory, receptivity is defined as the ability of students to understand a complex concept. Receptivity is highest when the topic is introduced and tends to decrease as time passes in a lecture. Suppose that the receptivity of a group of students in a mathematics class is given by
g (t) = - 0.2t2 + 3.1t + 32
where t is minutes after the lecture begins.
(a) At what rate is receptivity changing 10 minutes after the lecture begins?
(b) Write a sentence that explains the meaning of your answer in part (a).