Question

Pisces is replacing paving stones for her inground pool. Her pool is 10m by 5m and is surrounded by a 1 1/2 border of paving stone. If each paving stone was 25 cm by 40 cm, in theory, how many paving stones will she need?

Answer 1

The number of paving stones she needs is 540 paving stone

Explanation:

The given dimensions of Pisces' inground pool = 10 m by 5 m

The thickness of the border surrounding the pool = 1 1/2

The dimensions of each paving stone = 25 cm by 40 cm = 0.25 m by 0.4 m

The length dimension of the pool and border = 10 + 2 × 1 1/2 = 13 m

The width dimension of the pool = 5 + 2 × 1 1/2 = 8 m

The total area of the paving stone,
`T_A` = Area of pool + border - Area of pool

∴
`T_A` = 13 m × 8 m - 10 m × 5 m = 54 m²

The total area of the paving stone = 54 m²

The area of each paving stone,
`A_(EP)` = 0.25 m × 0.4 m = 0.1 m²/paving stone

The number of paving stones she needs, n = (The total area of the paving stone)/(The area of each paving stone)

∴ n = 54 m²/(0.1 m²/paving stone) = 540 paving stone.