Question

the length of a rectangular field is twice its breadth and its area is 2 hectares find the cost of fencing the field at rupees 50 per metre. the answer given in my book is rupees 30,000

Answer 1

Let the breadth = x
:. Length =2x

:. Area = (l x b) = x * 2x = 2x²

:. 2hectre = 2x²

20000m = 2x²

:. x² = 20000/2 = 10000m

:. x = 100m = Breadth......... (i)

2x = 200m = length..........(ii)

perimeter= 2( l+b ) = 2( 100 + 200 )
= 2(300) = 600m

cost per meter = Rs 50
Cost per 600m = Rs 50 x 600m =Rs 30000

Answer 2

Answer:

Let the breadth = x

:. Length =2x

:. Area = (l x b) = x * 2x = 2x²

:. 2hectre = 2x²

20000m = 2x²

:. x² = 20000/2 = 10000m

:. x = 100m = Breadth......... (i)

2x = 200m = length..........(ii)

perimeter= 2( l+b ) = 2( 100 + 200 )

= 2(300) = 600m

cost per meter = Rs 50

Cost per 600m = Rs 50 x 600m =Rs 30000