Question

If the length and breadth of a room are increased by 1m . The area of the room increased by 21 sq m . If the length is increased by 1m and breadth is decreased by 1m the area is decreased by 5 sq m . Find the perimeter of the room

Answer 1

Answer:

Pls mark as brainlest.   If it helps.

Let breadth be b and length be a.

So,

(a +1) (b + 1) = 21 + ab

ab + a + b + 1 = 21 + ab

a + b = 20

b = 20 - a

Now , we form the second equation;

( a + 1 ) (b - 1 ) = ab - 5

ab - a + b -1 = ab - 5

20 - a -a -1 = -5

-2a + 19 = -5

-2a = -19 - 5

a = -24 / -2    =>  a = 12    

And,   b = 20 - a = 20 - 12 = b = 8

Now using the formula for the perimeter;

2 ( l + b )   =>  2 (a + b )  = >  2 * 8 * 12 = 192