Question

If the length of a rectangular farm and its breadth are in the ratio 5 : 4 and the area of the farm is 13520 m², find the cost of fencing the farm at the rate of 15 per metre.
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Answer 1

Given :-

Ratio of length and breadth 5:4

Area = 13520 m²

Rate = 15 per m

To Find :-

Cost of fencing

Solution :-

$\sf Area = l \times b$

Let the sides be 5x and 4x

$\sf 13520 = 5x \times 4x$

$\sf 13520 = 20x^{2}$

$\sf \dfrac{13520}{20} = x^{2}$

$\sf 676 = x^{2}$

$\sf \sqrt{676} = x$

$\sf 26 =x$

Length = 5(26) = 130 m

Breadth = 4(26) = 104 m

Perimeter = 2(130 + 104)

Perimeter = 2(234)

Perimeter = 468 m

Cost = Perimeter  x Rate

Cost = 468  x 15

Cost = Rs 7020