I think the answer would be 9 or 18 not really sure
Without any calculations it's evident it can't be neither B (both numbers are even, so they're divisible by 2) nor C (the numbers end in 0 and 5, so they're divisible by 5).
A.

Both numbers have a factor of 3, so they're not relatively prime.
That means it must be D. But, let's check it.

Indeed, those two numbers are relatively prime.
Answer:
65 feet below sea level.
Step-by-step explanation:
With the information provided, we can create the following equation for the position of the sea lion (p)
p = 3x - 10
In this equation, x would be the final position of the seal when it caught the fish. Since we are told that the seal's position is 25 feet below sea level then we can plug in this value as x and solve for p...
p = (3 * 25) - 10
p = 75 - 10
p = 65
Finally, we can see that the sea lion's position is 65 feet below sea level.