The length of a rectangle is twice its breadth. If its length is decreased by 5 cm and breadth is increased by 5 cm, the area of the rectangle is increased by 75 sq. cm. Find the length of the rectangle.
Choose the correct choice:
A) 5
B) 10
C) 15
D) 20
E) None of them
Let breadth = x. Then, length = 2x. Then,   (2x - 5) (x + 5) - 2x * x = 75 &lt;=&gt; 5x - 25 = 75 &lt;=&gt; x = 20.   Therefore, Length of the rectangle = 20 cm.   Answer is 20
<result>D</result>
The length of a rectangle is twice its breadth. If its length is decreased by 5 cm and breadth is increased by 5 cm, the area of the rectangle is increased by 75 sq. cm. Find the length of the rectangle.