Question

In a mixture of $45$ litres, the ratio of milk and water is $4:1.$ How much water must be added to make the mixture ratio $3:2$?

• A. $18$ litres
• B. $15$ litres
  
• C. $21$ litres
  
• D. $25$ litres
  

Answer 1

Answer: (B)

$15$ litres

Quantity of milk in 45 litres of mixture $\frac{4}{5}\times 45litres=36litres$

$\therefore$ Quantity of water in the mixture $=9$ litres

Let $x$ litres of water be added to the mixture.

Then, $\frac{36}{9+x}=\frac{3}{2}\Rightarrow 72=27+3x\Rightarrow 3x=45\Rightarrow x=15litres.$