In shoreville, the last low tide was at 12: 00 a. m. about what time will the next high tide occur?

We don't know anything about Shoreville, or the coastline or shoreline
around it.  So the only answer we can offer is the broad world-wide average.

Between consecutive appearances of the moon at the same place in the sky,
there are two high and two low tides.

The moon appears to circle the entire sky in 29.531 days, whereas the
sky itself, referred to the sun, circles in 24 hours.  So the moon takes

                 (29.531 / 24)  =  1.2305 days

to return to the same place in the sky.

That period of time is also the cycle of the four tide extremes ... 2 highs
and 2 lows.  So the period between two extremes averages

              (1.2305 / 4)  =  0.3076  day  =  7.38 hours = 7h 23min .

If one extreme tide occurs at 12:00, we would expect the next one at  7:23 . 

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