Question

How many tiles, each of area 400 cm², will be needed to pave a footpath which is 2 m wide and surrounds a grass plot 25 m long and 13 m wide? 

Answer 1

Area of grass = l × b

= 25 × 13

= 325 m²

The footpath is 2 m wide and surrounds the grass plot.

The new length of the plot, including the footpath, is:

Total length = 25 m + 2 m + 2 m

= 29 m

The new width of the plot, including the footpath, is:

Total width = 13 m + 2 m + 2 m

= 17 m

The total area is calculated using the new dimensions:

Total area = l × b

= 29 m × 17 m

= 493 m²

The area of the footpath is found by subtracting the area of the grass plot from the total area:

Area of footpath = Total area − Area of glass

= 493 m² − 325 m²

= 168 m²

= 1680000 sq. cm

Total area = Number of tiles × Area covered by 1 tiles

⇒ 1680000 = Number of tiles × 400

⇒ Number of tiles = `(1680000)/(400)`

= 4200

Hence, the number of tiles = 4200.