Question

Length of rectangular blackboard is 8 more than its breadth. if its length is increased by 7 and its breadth is decreased by 4m its area remains unchanged. what is the length of the blackboard

Answer 1

let the length be l

and the breadth be b

according to the question,

l=b+8---------I)

and (l+7)(b-4)=l *b---------ii) area of a rectangle is length * breadth

substituting the value of l in eq.II)

(b+15)(b-4)=(b+8)(b)

b2-4b+15b-60=b2+8b

b2+11b-60=b2+8b

b2-b2-60=8b-11b

-60=-3bm

60=3bm

b=60/3m

b=20m

if the breadth is 20m

now substituting the value of b in equation I)

l=20+8

l=28m

hence the length is 28m and the breadth is 20m.

it was very easy . please mark brainiest if it is satisfactory.

Answer 2

Step-by-step explanation:

The correct answer. Please mark it at the brainliest