Practice using derivatives in a variety of different fields.

Problem

Alex learned 80 new vocabulary words for his English exam. The number of words he remembers after t days is given by the following function:
W, left parenthesis, t, right parenthesis, equals, 80, left parenthesis, 1, minus, 0, point, 1, t, right parenthesis, start superscript, 3, end superscript
What is the instantaneous rate of change of the number of words Alex remembers after 5 days?
Please choose from one of the following options.
In what units is this rate of change measured?
Please choose from one of the following options.