The half-life of the radioactive element unobtanium-29 is 5 seconds. If 48 grams of unobtanium-29 are initially present, how many grams are present after 5 seconds? 10 seconds? 15 seconds? 20 seconds? 25 seconds? The amount left after 5 seconds is grams The amount left after 10 seconds is grams. The amount left after 15 seconds is grams The amount left after 20 seconds is grams. The amount left after 25 seconds is grams (Round to one decimal place.)