Answer:
21
Explanation:
The amount added to each of the 3 sides is a rectangle 6.25 m by 1.5 m.
Then there are two square corners added that each one is 1.5 m by 1.5 m.
Total added area = 3 × 6.25 m × 1.5 m + 2 × 1.5 m × 1.5 m
Total added area = 28.125 m² + 4.5 m²
Total added area = 32.625 m²
The area of each tile is:
0.25 m × 0.25 m = 0.0625 m²
A box of tiles has 25 tiles. The total area covered by a box of tiles is:
25 × 0.0625 m² = 1.5625 m²
The number of boxes need is:
32.625 m² / 1.5625 m² = 20.88
Since 20.88 boxes are needed, but she needs to buy full boxes, she needs 21 boxes of tiles.
Answer: 21