Answer: r≤10.4
Explanation:
Initial depth - 12.8 feet
Maximum depth reached - 49.2 feet
49.2-12.8= 36.4 feet (maximum descent that the scuba diver can make)
Rate = Distance ÷ time
Distance - 36.4 feet
Time - 3.5 minutes
r=

r= 10.4
As r is the maxmimum rate found, r cannot be greater than 10.4, so r must be less than or equal to 10.4.
Therefore, r≤10.4