Question

How much water must be evaporated from 800 lb of a 10% salt solution to yield a solution that is 20 % salt?

Answer 1

400 lbs

Answer 2

you have 80 pounds of salt, (since 10% of 800 is 80) so the question becomes
" 80 is 20% of what number?" the answer is
\[.2\times x= 80\]
\[x=\frac{80}{.2}=400\] so you must get rid of 400 lbs of water