A 80 m by 64 m rectangular lawn has two roads, each 5 m wide, running through its middle, one parallel to its length and the other parallel to its breadth. Find the cost of gravelling the roads at RS. 40 per m2.

Given:


Length = 80 m


Breadth = 64 m


Width of road = 5 m


Cost = Rs 40 per m2



Area of horizontal road = 5 m × 80 m


= 400 m2


Area of vertical road = 5 m × 64 m


= 320 m2


Area of common part to both roads = 5 m × 5 m


= 25 m2


Now,


Area of roads to be gravelled = Area of horizontal road + Area of vertical road - Area of common part to both roads


= 400 m2 + 320 m2 - 25 m2


= 695 m2


Cost of gravelling = 695 m2 × Rs 40 per m2


= Rs 27800


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