Answer:
He is at sea level after 34 seconds
Step-by-step explanation:
The height at sea level is given as 0 meters
So the change in height would be;
0- (-17) = 17 meters
There is a gain of 0.5 meters in 1 second
So, the time taken for it to gain 17 meters will be 17/0.5 = 34 seconds
