Part A
We were told that the submarine descends 480 feet in 24 seconds. Since it is descending,the distance would be negative. Let x represent the descent in 1 second. Thus, the expressions would be
- 480 = 24
x = 1
By cross multiplying, we have
x * 24 = 480 * 1
24x = - 480
x = - 480/24
Thus, the correct option is the thrd one
Part B
Let the constant rate be x ft/sec
This means that after 8 seconds, the elevation change would be
8 * x
= 8 feet
