In what ratio should a 6.5 N HNO3 be diluted with water to get 3.5 N HNO3?

Using cross wise rule x=3.5-0=3.5y=6.5-3.5=3.0The dilution ratio is 3.5 : 3 or 7 : 6, i.e., 6 volumes of water should be added to 7 volumes of 6.5 N solution to get 3.5 N HNO3 solution.