Question

The length and the breadth of a rectangle are changed by +20% and by-10%, respectively. What is the percentage change in the area of the rectangle?

Answer 1

Answer:

let the length of the rectangle is 100

now it is increased by 20%

so, now length=(100+20)=120

again if breadth is 100 then now breadth is (100-10)=90

before change area is (100×100)=10000

now area us (120×90)=10800

area changed (10800-10000)=800

percentage change in area =800×100/10000

=8%