Lead-214 has a half life of 27 minutes if you started with 500 grams of this isotope how many grams would you have after 54 minutes

Every 27 minutes the amount of radioactive material is cut in half. So, starting with 500 grams, at T=27 minutes half of that original amount is remaining. And then after an additional 27 minutes (i.e. at T=54 minutes) half of the amount you had at T=27 minutes is remaining. How much is that?