Question

How many liters of water must evaporate from 50 liters of an 8% salt solution to make 25% salt solution?

Answer 1

8% of 50= 4.
means we have 4 parts of salt in 50 litres of water.
since salt content will remain same.
so 25% of x= 4.
so answer ths equation gives is 16.
therefore, 34 litres of water should evaporate.

Answer 2

mass of salt in 50 liters of 8% = 50*80 = 4000
for a 25% solution volume woold be 4*4000 = 16000
so 50 -16 = 34 will evaporate