Navigation General · Tides
Using the Rule of Twelfths, what fraction of the total tidal range has the tide risen after the FOURTH hour of flood?
- A6/12
- B9/12✓ Correct
- C3/12
- D10/12
Explanation
Cumulative fractions: 1st hr = 1/12, 2nd = 2/12, 3rd = 3/12, 4th = 3/12. Total after 4 hours = 1+2+3+3 = 9/12 of the range.
Authority: Bowditch (Pub. 9), Ch. 9
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