Answers:
Vertical distance traveled = 410.7 feet
Mean hourly vertical distance = 136.9 feet per hour
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Explanation:
We'll subtract the positive versions of the two numbers (large - small) to get
725.6 - 314.9 = 410.7
This tells us that the distance between those depth markers is 410.7 feet
In other words, the submarine has risen 410.7 feet in vertical distance over those 3 hours.
The mean hourly distance, aka the speed, is
speed = distance/time
speed = (410.7 feet)/(3 hours)
speed = (410.7/3) feet per hour
speed = 136.9 feet per hour
This is another way of saying "each hour, the submarine goes up by exactly 136.9 feet".
