Answer:
The new area of garden is 3 times of the initial area of the garden.
Explanation:
The initial length of the garden is 10 feet.
The shape of the garden must be a rectangle and the area of rectangle is

The initial area of the garden is


The new length of the garden is 30 feet. So, the new area of the garden is


Let area of garden is k times larger than the initial area.


Divide both sides by 10w.

Therefore new area of garden is 3 times of the initial area of the garden.