The length of rectangle is halved, while its breadth is quadrupled. What is the percentage change in the area?

100% increase

Let the length of the rectangle = 2units

and breadth = 1unit

Now if length is halved then length = 1unit

and breadth is quadrupled then breadth = 4units

Now,

Old area              New area

2×1                         1×4

 =2                         = 4

4 - 2 = 2 ( Increased )

Percentage increased = 2/2 × 100 = 100%