Question

In the theory of learning, the rate at which a subject is memorized is assumed to be proportional to the amount that is left to be memorized. suppose m denotes the total amount of a subject to be memorized and a(t) is the amount memorized in time t > 0. determine a differential equation for the amount a(t). (assume the constant of proportionality is k > 0. use a for a(t).)

Answer 1

The answer is in the picture, I can't add it.