Take the volume of your tea (in mL) and then divide the mass of the kratom by that number. This should give you something with the units g/mL. That tells you how many grams of kratom are present per mL of liquid. From the information you provided in the title you should have a tea with a kratom concentration of .02777... g/mL. Figure out the volume (in mL) of one of your measuring cups and multiply that by .02777..., the mL units will cancel and that'll tell how many grams are present in one of your measuring cups.