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The perimeter of a rectangular field is 84 metres. If the length of the field is increased by 2 metres andits breadth is decreased by 4 metres, the area is decreased by 32 sq m. Find the length and breadth of threctangular field.12. |
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Answer» suppose length and breadth is l and bso 2(l+b)=84so l+b=42 -> l=42-bnow l is increased by 2m and breadth is decreased by 4m, area is decreased by 32so (l+2)(b-4)=lb-32lb+2b-4l-8=(42-b)b-32(42-b)b+2b-4(42-b)=42b-b^2-2442b-b^2+2b-168+4b=42b-b^2-246b=144b=24so l=18b^2-48b+208=0 |
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