The cost of tiling the floor is Rs. 324.
The total cost of white washing the walls is Rs. 179.20 at the rate of Rs. 1.60 per square meter. The area of the four walls of the classroom is given by the formula:
Area of walls = 2 * (Length + Breadth) * Height
Length = 2h = 2 * 4 = 8
Breadth = 1.5h = 1.5 * 4 = 6
Now, the area of the floor is given by:
Area of floor = Length * Breadth = 8 * 6 = 48
The cost of tiling the floor at the rate of Rs. 6.75 per square meter is given by:
Cost of tiling = Area of floor * Rate of tiling = 48 * 6.75
= Rs. 324
Therefore, the cost of tiling the floor is Rs. 324.