The builder has to tile the inside of the house and the open patio outside,determine how many boxes of the tile the builder will need,size 9000mm,7 tiles per box,R185.99 per box?

First, we need to calculate the total area that needs to be tiled.

Inside of the house:
Assuming the house is a square with sides of 9000mm, the area to be tiled is 9000mm x 9000mm = 81,000,000 mm²

Outside patio:
Assuming the patio is also a square with sides of 9000mm, the area to be tiled is 9000mm x 9000mm = 81,000,000 mm²

Total area to be tiled = 81,000,000 mm² + 81,000,000 mm² = 162,000,000 mm²

Next, we need to calculate how many tiles are needed.
Each tile covers an area of 900mm x 900mm = 810,000 mm²
So, the total number of tiles needed is 162,000,000 mm² / 810,000 mm² = 200 tiles

Since there are 7 tiles per box, the builder will need 200 tiles / 7 tiles per box = 28.57 boxes

Since the builder cannot purchase a fraction of a box, the builder will need to purchase 29 boxes of tiles.

The total cost of the tiles will be 29 boxes x R185.99 per box = R5,389.71

Therefore, the builder will need 29 boxes of tiles at a total cost of R5,389.71.

Step 1: Calculate the total area to be tiled

- Inside of the house: 9000mm x 9000mm = 81,000,000 mm²
- Open patio outside: 9000mm x 5000mm = 45,000,000 mm²
- Total area: 81,000,000 mm² + 45,000,000 mm² = 126,000,000 mm²

Step 2: Convert the area to square meters

- 126,000,000 mm² / 1,000,000 = 126 m²

Step 3: Calculate the number of boxes of tiles needed

- 126 m² x (1 box / 7 tiles) = 18 boxes

Step 4: Calculate the total cost of the tiles

- 18 boxes x R185.99 = R3,347.82

Conclusion:

The builder will need 18 boxes of tiles to complete the job, at a total cost of R3,347.82.