Answer:
The answer to your question is the original dose of Ba-142 was 1184 μg
Explanation:
Data
Total time = 1.25 hours
The Final amount of Ba = 9.25 μg
The Half-life of Ba = 10.6 minutes
Process
1.- Convert total time to minutes
1 h ----------------- 60 min
1.25 h ------------ x
x = 75 min
2.- Draw a table of this process
Final amount of Ba Time
9.25 75 min
18.5 64.4 min
37 53.8 min
74 43.2 min
148 32.6 min
296 22 min
592 11.4 min
1184 0.8 min
