Question

The lenght of a rectangle exceeds its breadth by 7 cms . If the length is decreased by 4cm and the breadth is increased by 3cms. then the area of the new rectangle will be the same as the area of the original rectangle . what will be the perimeter of the original rectangle​

Answer 1

Answer:

perimeter = 50 cm

Step-by-step explanation:

let the length of original rectangle = l

let the breadth of original rectangle = b

l×b = A (area of original rect.)                       ----equation 1

l= 4 + b                                                        ----equation 2

( l - 4 )( b + 3 ) = A                                         ----equation 3

put value of A from equation 1 in equation 3

( l - 4)( b + 3 ) = lb

lb + 3l -4b - 12= lb

3( 4+ b) - 4b - 12 = 0                                (putting value of l from equation 2)

21+ 3b - 4b - 12 = 0

b = 9 cm

l = 4 + b = 4 + 9 = 16 cm

perimeter= 2 ( l + b ) = 2 ( 16 + 9) = 2 ( 25) = 50 cm