The function  is .

Where the original area of the wound is .

represents the area of the wound after days.

(a)

After how many days will the wound be one-half its original size.

Therefore,

Substitute   and  in .

From the definition   if and only if .

The area of the wound be one-half its original size after days.

(b)

How long before the wound is of its original size.

Original area is .

of its original size is

.

Substitute and   in .

From the definition   if and only if .

The wound is of its original size before days.

(a) The area of the wound be one-half its original size after days.

(b)The wound is of its original size before days.