The circumference is increased by 20× 2 = 40m, and 40 ÷10% = 400m-the original circumference.

400 ÷ 2 = 200m-the sum of the original length and width.

200×3/5 = 120m- original length.

200 120 = 80m- original width.

120×80=9600 m2-original area.