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Last Updated on May 3, 2023
GMAT OFFICIAL GUIDE PS –
Solution:
We start with 10,000 gallons of a solution that is 5% sodium chloride by volume. This means that there are 0.05 x 10,000 = 500 gallons of sodium chloride.
When 2,500 gallons of water evaporate we are left with 7,500 gallons of solution. From here we can determine what percent of the 7,500 gallon solution is sodium chloride.
(sodium chloride/total solution) x 100 = ?
(500/7,500) x 100 = ?
5/75 x 100 = ?
1/15 x 100 = ?
100/15 = 20/3 = 6 2/3 = 6.67%
Answer: D
