10 mL of a drink were diluted to volume in a 50 mL volumetric flask. A small portion was placed in a vial and analyzed by HPLC. The diluted sample was determined to contain 63 ppm caffeine. What mass of caffeine was present in the 50 mL volumetric flask after it was diluted to volume (before the portion was removed to place in the vial).

The answer is 3.2 mg caffeine.

How do you get to this conclusion? Show calculations.