A lawn is in the form of a rectangle whose sides are in the ratio 5 : 3. The area of the lawn is 3375 m2. Find the cost of fencing the lawn at RS. 65 per metre.

Given: Cost of fencing lawn = Rs 65 per metre.


Area of lawn = 3375 m2


Length: Breadth = 5: 3


Let,


Length = 5x


Breadth = 3x



We know that,


Area of lawn = Length × Breadth


3375 m2 = 5x × 3x


3375 m2 = 15x2



x2 = 225 m2


x = 15 m


Therefore,


Length = 5x = 5 × 15 = 75 m


Breadth = 3x = 3 × 15 = 45 m


Now,


Perimeter of lawn = 2(length + breadth)


= 2(75 m + 45 m)


= 2 × 120 m


= 240 m


Hence,


Cost of Fencing = 240 m × Rs 65 per meter


= Rs 15600


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