Answer: a. In this situation, 0 likely represents sea level or the baseline from which water levels are measured.
b. To find the average water level relative to high tide, you need to take the average of high tide and low tide.
Since high tide is 5 feet higher than low tide, you can assume that low tide is 0 ft. Therefore, the high tide is 5 ft.
The average of two values is the sum of the values divided by the number of values. So average of 0ft and 5ft is (0+5)ft / 2 = 2.5 ft.
Therefore, an integer that represents the average water level relative to high tide would be 2.5 ft.
It's worth noting that relative to high tide means how much the average water level varies (higher or lower) from the high tide, so the answer was not an integer in this case.