Striking clock problem?

Question

I woke up one night and heard my clock strike "one." I was too tired to turn on the light to see what time it was. As I lay there pondering, it occurred to me to speculate how long I would have to lie awake in order to be sure what was the exact time. My clock strikes the hours and strikes "one" each half hour. I fell asleep before I solved the problem, but can you work out what is the longest time I would have to lie awake after hearing the strike "one," to be sure of the time?

Answer 1

The strike I heard was either one o'clock or some half hour. If, after another half hour I hear two more strikes, I know what hour it is, but if I again hear one strike, I may have heard successively 12:30 am and 1 o'clock or 1 o'clock and 1:30 am. After another half hour I either hear 1 strike (1:30 am) or two strikes (2 o'clock). I may, therefore, have to lie awake a whole hour before I can be sure of the exact time.

Answer 2

You would possibly have to wait for an hour, if the time you awoke was either half past midnight or one o'clock am, since the clock would strike "one" for the half hour or the one o'clock.

It would then strike "one" again for one o'clock, or for one thirty, depending what time it was. Finally, after 1 hour, you would learn the actual time, because the clock would strike "one" for the third consecutive time at 1:30 had you woke up at 12:30, and would strike "two" if you awoke at 1 am.

Answer 3

4 times. wake up just after 12, so you hear the last strike from it. then 12:30 then 1:00 then 1:30

Answer 4

1 hour after hearing the first strike. If it strikes "one" twice more, than the 1st strike was 12:30. If it stikes "one", then "two, then it was 1:00.

Answer 5

About 10 seconds. If it wasnt your alarm clock going off, then its time to go back to sleep.

Answer 6

Just go to sleep

Answer 7

OUCH, my head hurts now thanks!!