14. Length of a rectangular blackboard is 8m more than its breadth. If

1.	14. Length of a rectangular blackboard is 8m more than its breadth. If its length is increased by 7 m and itsbreadth is decreased by 4 m, its area remains unchanged. What is the length of the blackboard?
Answer» Let the breadth of Reactangle blackboard = xThen length of Reactangle blackboard = x + 8 Area A1 = lengthbreadth = (x +8)x If length increased by 7 m and breadth decreased by 4 m Area A2 = lengthbreadth = (x + 15)(x-4) Given A1 = A2(x + 8)*x = (x + 15)(x - 4)x^2 + 8x = x^2 - 4x + 15x - 6011x - 8x = 603x = 60x = 60/3 = 20 Length of Reactangle blackboard = x + 8= 20 + 8 = 28 m

14. Length of a rectangular blackboard is 8m more than its breadth. If its length is increased by 7 m and itsbreadth is decreased by 4 m, its area remains unchanged. What is the length of the blackboard?

Answer»

Let the breadth of Reactangle blackboard = xThen length of Reactangle blackboard = x + 8

Area A1 = length*breadth = (x +8)*x

If length increased by 7 m and breadth decreased by 4 m

Area A2 = length*breadth = (x + 15)*(x-4)

Given A1 = A2(x + 8)*x = (x + 15)(x - 4)x^2 + 8x = x^2 - 4x + 15x - 6011x - 8x = 603x = 60x = 60/3 = 20

Length of Reactangle blackboard = x + 8= 20 + 8 = 28 m