A laboratory teacher had 1.5 litres of concentrated sulfuric acid. She replaces concentrated sulfuric acid with water after every class till the carton is empty. One student needs 10 ml of sulfuric acid mixture in every class. First class had 20 students and since then all other classes observed 10 students. Calculate total quantity of water with which mixture of sulfuric acid and water is replaced till carton is empty. Note 1.5 litres of concentrated sulfuric acid had 90% sulfuric acid and rest water