Answer:
48 / 3 = 16
1 / 16 of the original amount is to remain
4 half lives = 1/2 * 1/2 * 1/2 * 1/2 = 1/16
After 4 half lives 1/16 of the original amount is present
4 half-lives * 3.8 days / half-life = 15.2 days
After 15.2 days only 3 g will be present
