Question

How much water must be added to 12 L (liters) of a 40% solution of alcohol to obtain a 20% solution?

Answer 1

Answer:

Alcohol in 40% solution = 12 X 0.4 = 4.8 L.

If w L water is to be added for 30% solution,

( 12 + w ) X 0.3 = 4.8

So, w = (4.8-3.6)/0.3= 4 L..