A tank is filled to one quarter of its capacity with a mixture consisting of water and sodium chloride. The proportion of sodium chloride in the tank is 50% by volume and the capacity of the tank is 24 gallons. If the water evaporates from the tank at the rate of 0.5 gallons per hour, and the amount of sodium chloride stays the same, what will be the concentration of water in the mixture in 2 hours?	Choose the correct choice from the following choices:
A) 32% B) 36% C) 40% D) 44% E) 48%
The number of gallons in the tank is (1/4)24 = 6 gallons   The amount of sodium chloride is 0.5(6) = 3 gallons   At the start, the amount of water is 0.5(6) = 3 gallons   After 2 hours, the amount of water is 3 - 0.5(2) = 2 gallons   The concentration of water is 2 / (3+2) = 2/5 = 40%   The answer is 40%.
<result>C</result>
A tank is filled to one quarter of its capacity with a mixture consisting of water and sodium chloride. The proportion of sodium chloride in the tank is 50% by volume and the capacity of the tank is 24 gallons. If the water evaporates from the tank at the rate of 0.5 gallons per hour, and the amount of sodium chloride stays the same, what will be the concentration of water in the mixture in 2 hours?