Answer:
C. y = 4 - x
Explanation:
Given that the speed the river is flowing is 2 miles per hour and David is rowing upstream (against the flow) at a rate of 6 miles per hour, his overall speed to start is 6 -2 = 4 miles per hour.
If his rate is decreasing 1 mile for each hour, his rate is -1.
If 'x' represents the number of hours, than the rate times the hours is: -1(x) or -x
Putting the starting speed together with the decreasing rate over time:
y = 4 - x