Answer: 7.5kg
Explanation:
Since Bill made mortar mix and he used 24kg of sand and 5kg of cement. This means that for 1 kg of cement, (24/5) = 4.8 kg of sand is used.
Therefore, when he uses 36kg of sand, the kg of cement used will be:
= 36 / 4.8
= 7.5 kg
Therefore, he'll use 7.5kg of cement and 36kg of sand.