Respuesta :
5 grams will be left. After the first 1000 years, there will be half of 20 left, or 10. After 2000 years, half of 10 will remain, which is 5.
Answer:
5g
after 1000 we will have 20/2 which is 10
after 2000 we will have 10/2 which is 5
