Explanation:
The quotient of -256/6 represents the average rate of descent of the submarine, in feet per minute. To find this rate, we divide the total change in depth (-256 feet) by the time taken to descend (6 minutes):
-256 / 6 = -42.67...
The quotient is negative because the submarine is descending (i.e., decreasing in depth). The magnitude of the quotient is approximately 42.67 feet per minute, rounded to two decimal places.
Therefore, the correct answer is:
C. The depth of the submarine DECREASED by 42 2/3 feet per minute.