Nicole uses $$4\times2=8$$ ml of mouthwash every day.  $$500\div8=62$$ R $$4$$  So, $$62$$ days after $$12$$ April, the bottle of mouthwash will become empty.  There are $$18$$ remaining days in April and $$31$$ days in May.  $$62-18-31=13$$ 
Nicole has a $$500$$ ml bottle of mouthwash. Every morning, she uses two capfuls of mouthwash. Each capful contains $$4$$ ml of mouthwash.  If Nicole open a new bottle of mouthwash on $$12$$ April, on which of these dates will she use up the whole bottle of mouthwash? 
Options:
- $$12$$ June 
- $$13$$ June 
- $$14$$ August 
- $$15$$ August 