A mixture contains alcohol and water in the ratio 4 : 3. If 5 litres of water is added to the mixture, the ratio becomes 4 : 5. The quantity of alcohol in the given mixture is -

A. 3 litres

B. 4 litres

C. 15 litres

D. 10 litres

Answer: Option D

Solution(By Examveda Team)

Let the quantity of alcohol and water be 4x litres and 3x litres respectively
$$\eqalign{ & \frac{{4x}}{{\left( {3x + 5} \right)}} = \frac{4}{5} \cr & \Rightarrow 20x = 4\left( {3x + 5} \right) \cr & \Rightarrow 8x = 20 \cr & \Rightarrow x = 2.5 \cr} $$
Quantity of alcohol
= (4 × 2.5) litres
= 10 litres.