A scientist obtained a sample that contained 80 grams of radioactive Barium-122 that decays exponentially over time. The amount of Barium-122 that remained in the
sample at observed times is shown in the table.
Time
Mass Remaining
(minutes)
(grams)
0
80.0
1
56.6
2
40.0
3
28.3
4.
20.0
If the radioactive decay continues at the same rate, what is the amount of Barium-122
remaining at 7 minutes (to nearest tenth of a gram).