Subject: mathqa
Question: 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 ?
Option: 
A: 8.12 %
B: 6.12 %
C: 7.12 %
D: 9.12 %
Answer: A