A bucket contains 2 mixtures A and B in the ratio 3:2. If 5 liters of the mixture is replaced by 5 liters of liquid B, then the ratio of the two liquids becomes 3:5. How much of the liquid A was there in the bucket?  Options.
A) 8 liters  B) 10 liters  C) 12 liters  D) 15 liters  E) 18 liters

Rationale: "1 st ratio = 3 : 2 2 nd ratio = 3 : 5 difference of cross products ratio = 3 * 5 - 3 * 2 = 9 common factor of the 1 st ratio = ( quantity replaced / sum of terms in 1 st ratio ) + ( quantity replaced * term a in 2 nd ratio / difference ) = ( 5 / 5 ) + ( 5 * 3 / 9 ) = 1 + 5 / 3 = 2.67 quantity of a = 3 * 2.67 = 8 liters approximately answer is a"
Answer: A