<PRE><B>Question 4407</B>
Let x represent the amount of water to be added.
You can use the following guideline:
Amount of water in 10%  + Amount of water added = Amount of water in 5% solution
      10%(20)           +       0%(x)           =        5%(20+x)
0.1(20)+ 0 = 0.05(20+x) Now simplify the terms
2+0=1+0.05x
2 = 1 + 0.05x Substract 1 from both sides
2-1 = 1 +0.05x - 1
1 = 0.05x Divide both sides by 0.05
1/0.05 = 0.05x/0.05
x = 20
So, 20kg water must be added.</PRE>