Which equation represents the speed of the boat for x hours spent rowing

C. y = 4 - x

Step-by-step 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

you would have to sell 24 bracelets.

step-by-step explanation:

84/3.5 = 24