Question

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 ₹ 65 per metre.

Answer 1

Let the length and breadth of the rectangular lawn be 5xmand3 xm, respectively.

Given:

Area of the rectangular lawn  `3375m^2` 

⇒`3375=5x xx 3x` 

⇒`3375=15x^2` 

⇒`3375/15=x^2` 

⇒`225=x^2` 

⇒ `x=15` 

Thus, we have: 

`l=5x=5xx15=75m`  

`b=3x=3xx15=45 m` 

Perimeter of the rectangular lawn =`2(l+b) `

=`2(75+45) `

=`2(120) `

=`240 m` 

Cost of fencing 1 m lawn = Rs 65 

∴ Cost of fencing 240 m lawn = `240xx65=Rs 15,600`