Answer:
2 grams
Step-by-step explanation:
50 years is 5 half lives as 1 half life is 10 years.
64 divide 2 = 32-1 half life
32 divide 2 =16-2nd half life
16 divide 2 = 8-3rd half life
8 divide 2 = 4-4th half life
4 divide 2 = 2-5th half life
This means we will have 2 grams left of the radioactive substance after 50 years.
