<PRE><B>Question 153543</B>
How many kilograms of water must be evaporated from 50 kg of a 10% salt solution to obtain a 15% salt solution?
:
Let x = amt of water to be evaporated
:
The amt of salt remains the same, only the per cent changes, as water is removed 
.10(50) = .15(50-x)
:
5 = 7.5 - .15x
:
+.15x = 7.5 - 5
:
.15x = 2.5
x = {{{2.5/.15}}}
x = 16{{{2/3}}} kg to be evaporated
:
:
Check soluton
.1(50) = .15(50-16.67)
5 = .15(33.33)
5 = 4.9995 ~ 5</PRE>