Answer: 8 plates
Explanation:
The dimension of the tray is 90cm x 40cm.
Each plate has a radius of 8cm. Diameter = 2 × radius
Therefore, the diameter of each plate is 2 × 8 = 16 cm
There needs to be a 2cm gap around each plate. This means that the total distance covered by each plate along the row and column of the tray would be 16 + 2 + 2 = 20 cm
Assuming the column of the tray is 90 cm, the number of plates that each column can occupy would be 90/20 = 4.5 = 4
the number of plates that each row can occupy would be 40/20 = 2
Therefore, the number of plates that can fit on the tray would be
4 × 2 = 8 plates