Molarity? Concentration?

A student placed 15.0 g of glucose (C6H12O6) in a volumetric flask, added enough water to dissolve the glucose by swirling, then carefully added additional water until the 100.- mL mark on the neck of the flask was reached. The flask was then shaken until the solution was uniform. A 55.0-mL sample of this glucose solution was diluted to 0.500 L. How many grams of glucose are in 100mL. of the final solution?