A container contains a mixture of two liquids P and Q in the ratio 7 : 5. When 9 litres of mixture are drawn off and the container is filled with Q, the ratio of P and Q becomes 7 : 9. How many litres of liquid P was contained in the container initially?

• Suppose the can initially contains 7X and 5X of mixtures A and B respectively.
  
  Quantity of A in mixture left =7X - 7/12 x 9 litres = 7X - 21/4 litres.
  
  Quantity of B in mixture left = 5X - 5/12 x 9 litres = 5X - 15/4 litres.
  
  
  => 7X - 21/4 / 5X - 15/4 = 7/9
  => 252X - 189 = 140X + 147
  => X = 3.
  i.e 7X = 7x3
  
  So, the can contained 21 litres of A.
• 7 years agoHelpfull: Yes(0) No(0)