Question

Marilee is creating a garden in her yard. She needs to put up a fence to keep the animals out of it. She has 40 yards of fencing she can erect. This
situation is modeled using the equation A = -w+ 20w, where A is the area of the fence and w is the width of the fence. Using the equation,
what is domain when the maximum range is achieved? (1 point
• 100 yards
• 10 square yards
• 5 yards
• 10 yards

Answer 1

A(w) = -w^2 + 20w is a parabola with vertex at w = -b/(2a) = -20/(2·-1) = 10.
So the width that gives maximum area is 10 yards. (The maximum area then is A(10) = 100 square yards.)