Question

A lawn in the form of a rectangle whose sides are in the ratio5:3.The area of the lawn is 3375m². Find the cost of fencing the lawn at Rs.8.50 per metre.

Answer 1

ratio of sides =5:3
let length=l= 5x m
breadth=b= 3x m
area of rectangular lawn = 3375 m^2
lb=3375
(5x)(3x)=3375
15x^2=3375
x^2=3375/15
x^2=225
x= 15 m
therefore
l=5x=5×15=75m
b=3x=3×15=45m
length of fencing the lawn = perimeter of the rectangle
=2(l+b)
=2(75+45)
=2*120
=240m
cost 1m fencing = Rs8.50
cost of 240m fencing = 240×8.50
=Rs2040

Answer 2

Solution
Let the common ratio be x
Then length=5x. And breath=3x
Area of lawn=length*breath
As per condition ,
Area of lawn=3375m²
l*b=3375
5x*3x=3375
15x²=3375
x²=3375/15
x²=225
x=√225
x=15m
Length=5x=5*15=75m
Breath=3x=3*15=45m
Fencing length=2(l+b)
=2(75+45)
=2*120
=240m
Cost of fencing=Rs 8.50*240
=Rs2040