Alligation or Mixture problems
A can contains a mixture of 2 liquids A and B in proportion 7 : 5 when 9 liters of mixture are drawn off and the can is filled with B, the proportion of A and B becomes 7 : 9. How many liters of liquid A was contained by the can initially?
W 1 : A 1 W 2 : A 2 . . . . . W N : A N 2 : 3 4 : 5 5 : 7 W 1 W 1 + A 1 = 2 5 W 2 W 2 + A 2 = 4 9 W N W N + A N = 5 12 = 72/180 = 80/180 = 75/180 => 5 : 3 Therefore, the ratio is 5: 3