Answer:
C. dL/dt = k(100 - L)
Step-by-step explanation:
We have a list containing 100 words.
L = number of words memorized at time t.
At any time t, the number of words left to be memorized is 100-L.
Therefore:
[tex]\frac{dL}{dt}\propto 100-L\\ $Introducing k, a constant of proportion$\\\frac{dL}{dt}= k(100-L)[/tex]
The correct option is C.