Question

A mixture of $40$ litres of milk and water contain $10\%$ water. How much water must be added to make water $20\%$ in the new mixture?

Answer 1

361 Milk 41 water

(90 %) (10%)

$\downarrow$ $\downarrow$

New % $\Rightarrow$ 80% 20

4 1

If we add x liter of water in minute and

quantity of milk remains constant throughout

$\frac{36}{4+x}=\frac{4}{1}$

$x=5liters$