Calculating Water Quantity for Concrete

The problem asks for the quantity of water used in making concrete, given the amount of cement, the total mass of concrete, the water-cement ratio, and the concrete's density.

Identify Relevant Information

• Cement Used: 2 tons
• Water-Cement Ratio (w/c): 0.45
• Concrete Produced: 10 tons (Note: This is extra information not needed for this specific calculation)
• Concrete Density: 2.5 ton/m³ (Note: This is extra information not needed for this specific calculation)

Water Quantity Calculation

The water-cement ratio is defined as:

$ \text{w/c ratio} = \frac{\text{Mass of Water}}{\text{Mass of Cement}} $

We can rearrange this formula to solve for the Mass of Water:

$ \text{Mass of Water} = \text{w/c ratio} \times \text{Mass of Cement} $

Substitute the given values:

$ \text{Mass of Water} = 0.45 \times 2 \text{ tons} $

$ \text{Mass of Water} = 0.9 \text{ tons} $

Convert to Kilograms

To find the quantity in kilograms (kg), we use the conversion factor 1 ton = 1000 kg:

$ \text{Mass of Water (kg)} = 0.9 \text{ tons} \times 1000 \frac{\text{kg}}{\text{ton}} $

$ \text{Mass of Water (kg)} = 900 \text{ kg} $

Therefore, the quantity of water used is 900 kg.