Answer:
- sand = 300 kg
- gravel = 600 kg
- cement = 900 kg.
Step-by-step explanation:
Let us consider,
Amount of sand be 1x kg, amount of gravel be 2x kg and amount of cement be 3x kg.
Now, we have 1800 kg of dry concrete. As we know that Dry concrete can be made by mixing sand, gravel and cement.
Then,
sand + gravel + cement = dry concrete.


divide both sides by 6,

amount of sand = 1x
amount of gravel = 2x
amount of cement = 3x