help from a teacher

5
2
17:35
13:15
06:37
35:13
12:56
04:50
28:45
14:08
05:56
05:27
10:42
07:59
11:24
08:25
10:04
06:41
05:14
15:21
37:45
10:16
30:07
19:13
11:16
11:01
06:41
10:36
08:06
11:55
28:13
07:57
47:52
13:01
07:58
16:16
05:00
06:00
05:59
07:05
07:00
24:37