Question

A mixture of $40$ litres of milk and water contains $10\%$ of water. How much water is to be added to the mixture so that the water may be $20\%$ in the new mixture.

• A. $5$ Litres
• B. $4$ Litres
• C. $6.5$ Litres
• D. $7.5$ Litres

Answer 1

The correct option is A $5$ Litres

In mixture of $40$ litre water is $10$ i.e. $4$ litre.
Let x litre of water be added.
According to the question,
$\frac{4+x}{40+x}=\frac{20}{100}=\frac{1}{5}$

$20+5x=40+x$
$4x=20$
$x=5$