A student used 10 mL water instead of 30mL for the extraction of the NaCl from the mixture. How would this affect the calculated percentage of NaCl in the sample?

In this problem, the solute is sodium chloride, the salt while the solvent which comprise of a larger mass in the solution is water. When the solvent volume is decreased which is related to its mass, with the solute mass being held constant, then the concentration of salt increases. This is called concentration method.