Question

The perimeter of a rectangular field is 80 m. If the length of the field is decreased by 2m and its breadth

is increased by 2m, the area is increased by 36 m2

. Find the length and breadth of the rectangular field.

(A) 30,10 (B) 40,10 (C) 30,20 (D) None of these​

Answer 1

Answer:

(A) 30,10

Step-by-step explanation:

Let the length and breadth of the rectangular field be l and b.

According to the given information,

2(l + b) = 80

l + b = 40   ... (1)

Original Area = lb

 

Now, the new length = l - 2

new breadth = b + 2

New Area = (l - 2) (b + 2)

 

According to the given information,

(l - 2) (b + 2) = lb + 36

lb - 2b + 2l - 4 = lb + 36

2(l - b) = 40

l - b = 20   ...(2)

Adding (1) and (2), we get:

2l = 60

l = 30 So, b = 10

 

Thus, the length and breadth of the rectangular field are 30 m and 10 m respectively.