Question

A lawn is in the form of a rectangle whose sides are in the ratio 5:3 and its area is 3375 m² . Find the cost of fencing the lawn at ₹ 20 per metre.

Answer 1

Let the length and breadth of the lawn be 5x and 3x m, respectively.

Now,

Area of the lawn = \(5x\times3x=5x^2\)

\(\Rightarrow \) 15x2 = 3375

\(\Rightarrow \) \(x=\sqrt{\frac{3375}{15}}{}\)

\(\Rightarrow \) \(x=\sqrt{225}=15\)

Length = 5x = 5x15 = 75 m

Breadth = 3x = 3x15 = 45 m

∴ Perimeter of the lawn = 2(Length + breadth)

= 2(75 + 45) = 2 x 120 = 240 m

Total cost of fencing the lawn at Rs 20 per meter = 240 x 20 = Rs 4800