Question

A mixture of 80 liters of milk and water contain 10% water how much water must be added to make water 20% in the new mixture?

Answer 1

mixture of water and milk= 80L
% of water = 10%
therefore amount of water= 80*10/100 = 8L
water should be added to make it 20% water,
Let amount of water added be 'x'
Now, total mixture of water and milk= 80+x
amount of water added= 8+x
% of water in mixture=20%
therefore,
((8+x)/(80+x))*100=20
40+5x=80+x
4x=40
x=10 liters

Answer 2

10 litres of water should be added