Question

The length and breadth of the rectangle park are in the ratio 5 : 4 and its area is 2880 $m^2$, find the cost of fencing the park at the rate of Rs. 5 per metre.

• A. Rs. 1000
• B. Rs. 1050
• C. Rs. 1080
• D. Rs. 2000

Answer 1

The correct option is C Rs. 1080

Let the length and breadth of the rectangle as per the given ratio be 5$x$ and 4$x$.

We know, area of rectangle = length x breadth
So, the area of the rectangular park
= 5$x$ x 4$x$ = 20 $x^2$

According to the question,
Area of the rectangular park is ${2880}^2$.
So, 20 $x^2$ = 2880
$\Rightarrow$ $x^2$ = 144
$\Rightarrow$ $x$ = 12
So, 5$x$ = 5 × 12 = 60
4$x$ = 4 × 12 = 48

So, the perimeter of the park
= 2 (length + breadth)
= 2 (60 + 48)
= 2 × 108
= 216 cm

For 1 m, the cost of fencing = Rs. 5
For 216 m, the cost of fencing
= Rs. 5 x 216
= Rs. 1080