Concentration refers to the amount of solute dissolved in a specific amount of solvent. To compare concentrations, the amount of solute must be measured within the same volume of solvent. In the example given, Solution A contains 10g of salt dissolved in 50mL of water, while Solution B contains 3g of salt dissolved in 10mL of water. Calculating the concentration per 100mL, Solution B contains 30g of salt per 100mL and is therefore more concentrated than Solution A which contains 20g of salt per 100mL. A saturated solution contains the maximum amount of solute that can dissolve at a given temperature, while an unsaturated solution can still dissolve more solute.