African Concrete Blocks is a company that manufactures square concrete blocks - NSC Mathematical Literacy - Question 3 - 2019 - Paper 1

To find the volume of one concrete block, we will use the formula:

$$ext{Volume} = ext{side} imes ext{side} imes ext{height}$$

Given that the side length is 50 cm (0.5 m) and the height is 180 mm (0.18 m), we can perform the calculation as follows:

$$ext{Volume} = 0.5 imes 0.5 imes 0.18 = 0.045 ext{ m}^3$$

Firstly, calculate the area of one concrete block using the formula:

ext{Area} = ext{side} imes ext{side}\

For one block:

$$ext{Area} = 0.5 imes 0.5 = 0.25 ext{ m}^2$$

Now, for 12 blocks:

$$ext{Total Area} = 12 imes 0.25 = 3 ext{ m}^2$$

Using the formula for the area of the walkway:

ext{Area} = ext{length} imes ext{breadth}\

Given that the dimensions are 4.05 m and 1.45 m:

$$ext{Area} = 4.05 imes 1.45 = 5.8725 ext{ m}^2$$

The area that needs to be covered with pebbles is:

$$ext{Area to be covered} = ext{Total area of walkway} - ext{Area of concrete blocks}$$

From previous calculations:

$$ext{Area to be covered} = 5.8725 - 3 = 2.8725 ext{ m}^2$$

Now, if one bag covers 0.36 m², the total number of bags required is:

$$ext{Number of bags} = \frac{2.8725}{0.36} ext{ bags} \approx 7.98 \text{ bags} \approx 8 ext{ bags (rounding up)}$$