I had to look up the answer[0].

> Due to the Moon's orbital prograde motion, it takes a particular point on the Earth (on average) 24 hours and 50.5 minutes to rotate under the Moon, so the time between high lunar tides fluctuates between 12 and 13 hours, generally being 12 hours and 26 minutes. So, if the tide has affected the place at 6:00AM, then it would generally take around 12 hours and 26 minutes for the place to be affected by Ebb i.e 6:00 AM+12 hrs+26 mins=6:26 PM.

Seems like a pretty tough question for a child?

[0]: https://www.toppr.com/ask/en-my/question/if-a-place-is-affec...

I agree - I don't see how this could be answered outside of guessing without outside information.

I assume that these are meant to be universally understood. If the tests were given in fishing villages, it may have been a much easier premise since much of their world is defined by the tides.