Problem Solving (PS) | Re: An alarm of a certain clock rings every 20 minutes. If the clock's ala

@Buenel

My Answer is D here
just to prove D is correct and official answer is may be wrong.
first ring - 15:20
2nd 15:40
3rd 16:00
4th. 16:20
5th. 16:40
6. 17:00
7. 17:20
8. 17:40
9. 18:00
10. 18:20
11. 18:40
12th ring 19:00
Kudos for correct answer.
Also would like to mention i correctly answered https://gmatclub.com/forum/an-alarm-of-
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