Assuming that tide duration from low tide to high tide is 6 hours and 25 minutes, going from a high of 3.21ft and down to a low of 0.20ft what is the lapse rate per hour of the tide?

To answer this you will need to write the ratio of difference in the tides over the amount of time that goes by.

1. 3.21 ft - 0.20 ft= 3.01 ft change.
2. 3.01 change over 6 5/12 hr.
3. Divide these to find the lapse rate per hour. This is about 0.47 ft per hour.

36.75 because 21/4 = 5.25 and 36.75/7 = 5.25