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The perimeter of rectangle is 80m. If the breadth increased by 2m and the length decreased by 2m, the area of the rectangle increases by 36m². Assuming the length to be x, obtain an equation. Also, find the length and breadth of the rectangle. |
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Answer» Answer: LET the LENGTH of the field = x breadth = y perimeter = 2(x+y) =80 ⇒ x+y = 80/2 ⇒ x+y = 40 Area = xy If the length is decreased by 2m and breadth is INCREASED by 2m, new length = (x-2) new breadth = (y+2) area = (x-2)(y+2) = xy + 2x -2y - 4 this area is 36 m² more than earlier area. So (xy + 2x -2y - 4) - (xy) = 36 ⇒2x -2y - 4 =36 ⇒2x - 2y = 36+4 = 40 ⇒ x-y = 20 Add the 2 equations, we get 2x = 60 ⇒ x = 30m y = 10M Hence length = 30m breadth = 10m |
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