Answer :
To solve this problem, we need to use the given ratio of cement to sand, which is 2 parts cement to 5 parts sand. The total number of parts is the sum of the parts of cement and sand:
Total parts = 2 parts (cement) + 5 parts (sand) = 7 parts.
The goal is to make 42 kg of mortar, so each 'part' of the mixture must weigh equally when combined to make up the entire 42 kg of mortar.
To find the weight of one part, we divide the total weight by the total number of parts:
[tex]\text{Weight of one part} = \frac{42 \text{ kg}}{7 \text{ parts}} = 6 \text{ kg per part}.[/tex]
Now, we calculate how much cement and sand is needed using the part weights:
Cement:
[tex]2 \text{ parts} \times 6 \text{ kg per part} = 12 \text{ kg of cement}[/tex]Sand:
[tex]5 \text{ parts} \times 6 \text{ kg per part} = 30 \text{ kg of sand}[/tex]
Therefore, to make 42 kg of mortar with the given ratio, the builder needs 12 kg of cement and 30 kg of sand.
