A tank contains 10,000 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?
(A) 1.25%
(B) 3.75%
(C) 6.25%
(D) 6.67%
(E) 11.7%
[spoiler] The correct answer is D. The solution is that since 5% is sodium chloride, thus 500 gallons are sodium chloride and 9500 gallons are water. If 2,500 gallons of water were evaporated, then it would be 10,000- 2,500 =7500. And 500/ 7500 is about 6.667%.
BUT:
The question is saying 2,500 gallons of WATER evaporated, not sodium chloride! (Plus sodium chloride is a salt compound and I don't think it evaporates anyway.) So shouldn't it be 9500 -2,500 and then 500/7000 = 7.14%? Thankfully, D is still the closest answer. But, I would certainly be very unhappy if this appeared on the real test and the options for the answer choices include 6.67% and 7.14%. [/spoiler]
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?
(A) 1.25%
(B) 3.75%
(C) 6.25%
(D) 6.67%
(E) 11.7%
[spoiler] The correct answer is D. The solution is that since 5% is sodium chloride, thus 500 gallons are sodium chloride and 9500 gallons are water. If 2,500 gallons of water were evaporated, then it would be 10,000- 2,500 =7500. And 500/ 7500 is about 6.667%.
BUT:
The question is saying 2,500 gallons of WATER evaporated, not sodium chloride! (Plus sodium chloride is a salt compound and I don't think it evaporates anyway.) So shouldn't it be 9500 -2,500 and then 500/7000 = 7.14%? Thankfully, D is still the closest answer. But, I would certainly be very unhappy if this appeared on the real test and the options for the answer choices include 6.67% and 7.14%. [/spoiler]
