In other words, the time to ring the bell is zero.
So there are pictures.
| - | - | - | - | - |-
The first "-"is a duration of two seconds. The second "-"is the interval time.
Because there was no interval between the last shots.
So there is (32-2)/5=6.
That is, the interval is 6-2=4.
So under 12, there is 1 1 times 6+2=68 seconds.