Original breadth of a rectangular box is 20 cm. The box was then remade in such a way that its length increased by 30% but the breadth decreased by 20% and the area increased by 100 cm$$^2$$. What is the new area of the box?

Let the length of the rectangle be l cm
Breadth of the rectangle = 20 cm
Area of the rectangle = 20l sq.cm
New length of the rectangle = 130% of l = 1.3l cm
New breadth of the rectangle = 80% of 20 = 16 cm
New area of the rectangle = 16*1.3l = 20.8l sq.cm
Given, 20.8l - 20l = 100
=> 0.8l = 100 => l = 125 cm
Therefore, New length of the rectangle = 1.3*125 = 162.5 cm
New area of the rectangle = 162.5*16 = 2600 sq.cm