The swimming pool has the shape of a cube, the edge of which is 5 m.

The swimming pool has the shape of a cube, the edge of which is 5 m. How many 20cm x 25cm slabs are needed to cover the walls and bottom of the pool.

In order to calculate how many tiles are needed for the walls and bottom of the pool, it is necessary to determine their area.
Because the pool has the shape of a cube, then all its sides and the bottom are a square with a side of 5 m.
The area of ​​the bottom and the area of ​​the side will be S = 5 * 5 = 25 square meters.
the pool has four sides and a bottom, which means that tiles must be covered with an area of ​​size S = 4 * 25 + 25 = 125 square meters.
Now let’s determine the area of ​​one tile. The dimensions of the tiles are converted into meters and we get 0.2m x 0.25m. Thus, the area of ​​the tile will be: S = 0.2 * 0.25 = 0.05 square meters.
By dividing the pool surface area by the tile area, we get the required number of tiles:
125: 0.05 = 2500 pieces.
Answer: 2500 pieces.