Question

length and breadth of a rectangle increased by 30% 25% respectively find the percentage increase in the area

Answer 1

Let the length be x
Breadth be y

So area of rectangle = l × b
=> xy
Percentage incteased in length = 30%
Increased in length = 130 / 100 × x
=> 13x/ 10
Percentage incresed in breadth = 25 %
Increased in length = 125 / 100 × y
=> 5y / 4
New area of rectangle = 13x / 10 × 5y / 4

=> 65xy / 40

Increased in area = 65xy / 40 - xy
=> 65xy - 40xy / 40
=> 25xy / 40
=> 5xy / 8

Percentage increased = 5xy / 8 ÷ xy × 100
=> 5xy / 8 × 1/ xy × 100
=> 5/ 8 × 100
=> 62.5%