A tank contains 6,500 gallons of a solution that is 5 percent sodium chloride by volume. If 2,500 gallons of water evaporate from the tank, the remaining solution will be approximately what percent sodium chloride?  Choices:
A) 5.12%  B) 6.12%  C) 7.12%  D) 8.12%  E) 9.12%
We start with 6,500 gallons of a solution that is 5% sodium chloride by volume. This means that there are 0.05 x 6,500 = 325 gallons of sodium chloride.   When 2,500 gallons of water evaporate we are left with 4,000 gallons of solution. From here we can determine what percent of the 4,000 gallon solution is sodium chloride.   (sodium chloride/total solution) x 100 = ?   (325/4,000) x 100 = ?   0.0812 x 100 = ?   = 8.12%   Answer is 8.12%.
<result>D</result>
A tank contains 6,500 gallons of a solution that is 5 percent sodium chloride by volume. If 2,500 gallons of water evaporate from the tank, the remaining solution will be approximately what percent sodium chloride?