Final answer:
The sum of the Atlantic Ocean's average depth and greatest depth is 43126 feet. Subtracting the greatest depth (assumed to be the deepest part of the Mariana Trench in feet) from this sum provides the average depth in feet. This result should be compared with known average depths for reasonableness.
Step-by-step explanation:
The student is asked to use the provided equation, which indicates the sum of the Atlantic Ocean's average depth in feet and its greatest depth is 43126 feet. The equation can be set up as Average Depth + Greatest Depth = 43126. According to the information given, the greatest depth (assuming it refers to the Mariana Trench as the deepest known point) is approximately 36090 feet (converting 11 km to feet).
To find the average depth, we would subtract the greatest depth from the total sum, which gives us:
Average Depth = 43126 - 36090
Average Depth = 7036 feet
To check if this answer is reasonable, we compare it with the known rough estimate of the ocean's average depth which is approximated as 12000 feet. Since our calculated average depth is significantly lower, additional information regarding the ocean depth specific to the Atlantic might be required to provide a more accurate estimate.