formula for half life

2:45

18:02

16:01

7:44

4:54

2:12

3:39

4:44

6:27

9:55

10:30

9:29

3:53

3:02

4:23

7:09

4:46

7:57

8:04

7:38

9:30

18:45

10:21

3:25

3:13

11:38

6:47

7:22

5:48

6:14

8:42

3:31

3:33

25:12

6:46

7:34

3:44

4:27

2:45

3:41

00:44

7:23

3:00

7:01

4:03

4:00

2:15

1:38

12:36

1:11:19

3:34

2:15

11:45

12:06

11:14

3:01

17:21

9:46

9:37

7:06