Sandy Wishes to Have a Rectangular Garden in Her Backyard $f(x)=40 x-x^{2}, \quad 0$

Multiple Choice

Sandy wishes to have a rectangular garden in her backyard. She has 40 ft of fencing with which to enclose her garden. Letting x denote the width of the garden, find a function f in the variable x that gives the area of the garden.

A) $f(x) =40 x-x^{2}, \quad 0$ $< x$ $<20$ .
B) $f(x) =20 x-x^{2}, \quad 0$ $< x$ $<20$
C) $f(x) =40 x-x^{2}, \quad 0$ $< x$ $<40$
D) $f(x) =20 x-x^{2}, \quad 0$ $< x$ $<20$ .