To reduce 16 ounces of a 25% solution of antiseptic to a 10% solution, how much distilled water should a nurse add?
Here's a more intuitive approach to use here.
The target solution must have a concentration of
Your starting solution has a volume of
In order to get to a solution that has a total of
#"1 part " = " 4 ounces"#
it follows that you must add
#6color(red)(cancel(color(black)("parts"))) * "4 ounces"/(1color(red)(cancel(color(black)("part solvent")))) = "24 ounces"#
of distilled water, which is your solvent, to the initial solution.
The target solution will contain