The diluted wine contains only 8 liters of wine and the rest is water. A new mixture whose concentration is 30%, is to be formed by replacing wine. How many liters of mixture shall be replaced with pure wine if there was initially 32 liters of water in the mixture?	Select the correct option.
A) 2 B) 5 C) 6 D) 7 E) 8

Rationale: explanation : wine water 8 l 32 l 1 : 4 20 % 80 % ( original ratio ) 30 % 70 % ( required ratio ) in ths case , the percentage of water being reduced when the mixture is being replaced with wine . so the ratio of left quantity to the initial quantity is 7 : 8 therefore , \ frac { 7 } { 8 } = \ left [ 1 - \ frac { k } { 40 } \ right ] \ rightarrow \ frac { 7 } { 8 } = \ left [ \ frac { 40 - k } { 40 } \ right ] \ rightarrow k = 5 l answer : b ) 5
Answer: B