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The area of a rectangle gets reduced by 9 square units. If it's length is reduced by 5 units and breath is increased by 3units .the area is increasing by 67 square units. If length is increasing by 3 unit and breath is increasing by 2 units then find the perimeter of the rectangle |
Answer» Answer:● PERIMETER of rectangle is 52 units.
Step-by-step explanation:Let , length and breadth of Rectangle be l and b respectively. then, area of rectangle will be l b First case : when length is reduced by 5 units and breadth is INCREASED by 3 units then, area of rectangle is reduced by 9 sq. units. so, → ( l - 5 ) ( b + 3 ) = l b - 9 → l b + 3 l - 5 b - 15 = l b - 9 → 3 l - 5 b - 15 = - 9 → 3 l - 5 b = 6 → 3 l = 6 + 5 b → l = ( 6 + 5 b ) / 3 ____eqn① Second case : when length is increased by 3 units and breadth is increased by 2 units then area of rectangle is increased by 67 sq. units. so, → ( l + 3 ) ( b + 2 ) = l b + 67 → l b + 2 l + 3 b + 6 = l b + 67 → 2 l + 3 b = 67 - 6 → 2 l + 3 b = 61 [ using equation ① ] → 2 ((6+5b)/3) + 3 b = 61 → (12 + 10 b)/3 + 3 b = 61 [ multiplying by 3 both sides ] → 12 + 10 b + 9 b = 183 → 19 b = 183 - 12 → 19 b = 171 → b = 171 / 19 → b = 9 units [ putting VALUE of b in eqn ① ] → l = ( 6 + 5 b ) / 3 → l = ( 6 + 5 (9) ) / 3 → l = 51 / 3 → l = 17 units Therefore, Length and breadth of rectangle are 8 units and 17 units respectively. so, → perimeter of rectangle = 2 ( l + b ) → perimeter of rectangle = 2 ( 9 + 17 ) → perimeter of rectangle = 52 units. Therefore, perimeter of rectangle is 52 units. |
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