Question

Find the cost of fencing a rectangular garden at the rate of rupees 7.5 per m if its length and breadth are in the ratio of 4:5 and its area is 1200m²

Answer 1

Let the length of field be 4x
, then the breadth is 5x
Area = length × Breadth
5x × 4x = 1200
$20x^{2} = 1200$
$x^{2} = 60$
So x = 4√15 m
Now length = 4x = 16√15 m
and breadth = 5x = 20√15 m
Perimeter = 2(l+b)
= 2(16√15 + 20√15)
=2 (36√15) m = 72√15 m

Cost of fencing= 7.5 rupee per m
So the price = 7.5 × 72√15 rupee
= 2091.411 rupee

HOPE IT HELPS!!