# half life

posted by
**julie** on
.

If the radiological half life of a material is 31 minutes, and you have 77 grams

now, how much did you have 55 minutes ago?

posted by
**julie** on
.

If the radiological half life of a material is 31 minutes, and you have 77 grams

now, how much did you have 55 minutes ago?