A container contains acid and water in the ratio of 5 : 4 respectively. 20% of the total is drawn off and replaced by water, Find the new ratio of water and acid now.

4 : 5

Acid   :   Water

 5      :       4

Let the quantity of acid & water = 90 liters

20% of 90 is drawn off & replaced with water i.e. 18 liters

Acid drawn off = 18 × \(\frac{5}{9}\) = 10 liters

Water drawn off = 18 × \(\frac{4}{9}\) = 8 liters

  Water   :      Acid

50 - 10   :   40 - 8 + 18

    40      :      50

      4      :      5