Part 1
Remember that
The rate of change is the same that the first derivative
so
The rate of change appears to be zero at times
t=1 weeks
t=4 weeks
t=6 weeks
Part 2
which of the following is true?
Verify each option
W'(3) > W'(7) -----> is not true
W'(3) < W'(7) -----> is true
W'(3)=W'(7) is not true
which of the following is true?
Verify each option
W'(0) < W'(5) -----> is true
therefore
the graph is