Given that length of lane = 180 m
Breadth of the lane = 5 m
Area of a lane = Length x Breadth
= 180 m x 5 m
= 900 m2
Length of the brick = 20 cm
Breadth of the brick = 15 cm
Area of a brick = Length x Breadth
= 20 cm x 15 cm
= 300 cm2
= 0.03 m2 [Since 1 m2 = 10000 cm2]
Required number of bricks = 900/0.03 = 30000
Cost of 1000 bricks = Rs. 750
Total cost of 30,000 bricks = 750×30,000/1000
= Rs. 22,500