Question 823895
<pre>
It rings at these times:

 1.  12:00
 2.  12:01
 3.  12:02
 4.  12:03
 5.  12:04
 6.  12:05
 7.  12:06
 8.  12:07
 9.  12:08
10.  12:09
11.  12:10
12.  12:11
13.  12:12
14.  12:13
15.  12:14
16.  12:15

Answer: 16 times.

Edwin</pre>