The rate at which weight is lost by an animal suffering from a viral infection is observed to satisfy the relationship for . Here is the weight loose, as a percentage of the animals original weight, weeks from the time of infection. Find the function giving the percentage weight loss at time , and determine the percentage weight loss when the animal dies eight weeks later.

Source: Rosenberg, R.L. (1984). Elementary Calculus: Course Notes. Ottawa, Canada: Holt, Rinehart and Winston. (Exercise 44: Question 3, p. 132)