Final answer:
To calculate the scuba diver's ascent time, divide the total depth by the ascent rate yielding 5.5 minutes.
Step-by-step explanation:
The student's question is about calculating the time it will take for a scuba diver to return to the surface from a depth of 165 feet if the safe ascent rate is 30 feet per minute. To find the answer, we divide the total depth the diver needs to ascend by the rate of ascent.
Total depth to ascend = 165 feet
Safe ascent rate = 30 feet per minute
Time to ascend = Total depth to ascend ÷ Safe ascent rate
Time to ascend = 165 feet ÷ 30 feet/minute
Time to ascend = 5.5 minutes
Therefore, the correct answer is (a) 5.5 minutes.