Question

The length and breadth of the rectangle park are in the ratio 5:4 and its area is 2420 $m^2$, find the cost of fencing the park at the rate of $10 per meter.

• A. $2080
• B. $1080
• C. $1980
• D. $1880

Answer 1

The correct option is C

$1980

Let the common ratio be x,

Then, length of rectangular park = 5x

Breadth of rectangular park = 4x

Area of rectangular park = 5x $\times$ 4x

= 20x${}^2$

According to the question,

20x${}^2$= 2420

$\Rightarrow$ x${}^2$=2420/20

$\Rightarrow$ x${}^2$= 121

$\Rightarrow$ x = 11

Therefore, 5x = 5 $\times$ 11 = 55 and 4x = 4 $\times$ 11 = 44

So, the perimeter of the rectangular park = 2 $\times$ (l + b)

= 2 (55 + 44)

= 2 $\times$ 99

= 198 cm

For 1 m, the cost of fencing = $10

For 198 m, the cost of fencing = $198 $\times$ 10

= $1980