A mixture contains alcohol and water in the ratio 4 : 3. If 6 litres of water is added to the mixture, the ratio becomes 4: 5. Find the quantity of alcohol in the given mixture  Choose the correct choice.
A) 15 litres
B) 10 litres
C) 30 litres
D) 12 litres
E) 8 litres
Let the quantity of alcohol and water be 4x litres and 3x litres respectively   4x/(3x+6)=4/5   20x=4(3x+6)   8x=24   x=3   Quantity of alcohol = (4 x 3) litres = 12 litres.   Answer is 12 litres
<result>D</result>
A mixture contains alcohol and water in the ratio 4 : 3. If 6 litres of water is added to the mixture, the ratio becomes 4: 5. Find the quantity of alcohol in the given mixture