Problema Solution
40 liters of a 60% salt solution are reduced to a 45% solution. How much solution must be drained off and replaced with distilled water so that the resulting solutions contains only 45% solution.
Answer provided by our tutors
you are just diluting with water. So to set this up, you need to know what level of water at .60 will make 40 liters at .45. To do this- here is what you do:
consider if x litre is drained off and replaced with water will give us 40 litres of 45% salt solution
(40-x)(.6)=40(.45)
24 -.6x = 18
-.6x = -6
x = 10
you need to drain off 10 litres and add 10 litres distilled water