If the length of a rectangle is increased by 12% and the breadth is decreased by 8%, the net effect on the area is:

increase by 3.04%

12% =  \(\frac{3}{25}\)  &  8% =  \(\frac{2}{25}\)

                         Old    :      New

Length                25     :       28

Breadth              25     :       23    

--------------------------------------------

Area                  625     :    644

Net change in area =  \(\frac{644 - 625 }{625}\) × 100 

=  \(\frac{19 }{625}\) × 100 

= 3.04%

Ans :- increase by 3.04%