Answer:
The number of paving stones she needs is 540 paving stone
Step-by-step 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, = Area of pool + border - Area of pool
∴ = 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, = 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.