Answer:
46%
Explanation:
When solving this problem we have to note that the amount of salt (in grams) before isolation and after isolation are equal. If [tex]V_1[/tex] represents its volume before isolation and [tex]V_2[/tex] its volume after isolation then:
[tex]2.1 \frac{g}{L} *V_1=3.89\frac{g}{L} *V_2\\\\\frac{V_2}{V_1} =\frac{2.1}{3.89}\\\\\frac{V_2}{V_1} =0.54\\\\This\ means\ after \ isolation\ the\ volume\ of water\ is\ 54\%\ of\ its\ original\ value.\\\\The\ amount\ of\ evaporation=1-\frac{V_2}{V_1} =1-0.54=0.46=46\%\\\\The\ amount\ of\ evaporation=46\%[/tex]