Final answer:
At high tide, there will be 4 rungs underwater.
Step-by-step explanation:
The boat has a ladder with six rungs, each one foot apart. The bottom rung is one foot from the water. The tide rises 12 inches every 15 minutes. High tide peaks in one hour.
To determine how many rungs are underwater at high tide, we need to calculate the total rise of the tide.
Given that the tide rises 12 inches every 15 minutes, we can calculate the total rise in one hour by multiplying the rise per interval by the number of intervals:
Rise per interval = 12 inches
Number of intervals in one hour = 4
Total rise in one hour = 12 inches x 4 = 48 inches
Since each rung is one foot apart, we can convert the total rise to feet by dividing it by 12 inches per foot:
Total rise in one hour = 48 inches ÷ 12 inches/foot = 4 feet
Therefore, at high tide, when the tide is at its highest, there will be 4 rungs underwater.