Question

Ravi is making a mixture of sand, cement and water. He adds 6 kg of cement and 4
litres of water to every 10 kg of sand.
Which of these statements is not correct?
1) The water is 20 % of the mixture.
2) The ratio of sand to cement to water is 5:2:3.
3) To make 30 kg of mixture, Ravi needs 9 kg of cement.
4) If he uses 4.5 kg of cement, then he needs 3 L of water.