The actual area of a rectangle is 60 Cm2, but while measuring its length a student decreases it by 20% and the breadth increases by 25%. The percentage error in area, calculated by the student is :

Answer: Option D

100 === 25% ↑===> 125 ===> 20% ↓===> 100
So there is no change in the area of rectangle

Alternatively :
Let area be 1
Area of rectangle,
= l × b
= 0.8 × 1.25
= 1